diff --git a/frontend/src/pages/Windows.jsx b/frontend/src/pages/Windows.jsx
index 21bdba5..197b311 100644
--- a/frontend/src/pages/Windows.jsx
+++ b/frontend/src/pages/Windows.jsx
@@ -1,149 +1,300 @@
-import { useEffect, useState, useMemo } from 'react'
+import { useEffect, useState, useMemo, useRef } from 'react'
 import api from '../api/client'
 import StatusBadge from '../components/StatusBadge'
 import WindowsPanel from '../components/WindowsPanel'
-import { Search, Monitor } from 'lucide-react'
+import { Search, ChevronUp, ChevronDown, Settings2, X } from 'lucide-react'
 
-function fmtPct(v) {
-  if (v === null || v === undefined) return '—'
-  return `${Number(v).toFixed(0)}%`
+const ALL_COLUMNS = [
+  { id: 'customer',     label: 'Kunde',           default: true },
+  { id: 'name',         label: 'Name',             default: true, locked: true },
+  { id: 'hostname',     label: 'Hostname',         default: false },
+  { id: 'os',           label: 'OS',               default: true },
+  { id: 'version',      label: 'Agent Version',    default: true },
+  { id: 'ip',           label: 'IP',               default: true },
+  { id: 'uptime',       label: 'Uptime',           default: true },
+  { id: 'cpu',          label: 'CPU',              default: true },
+  { id: 'ram',          label: 'RAM',              default: true },
+  { id: 'disk',         label: 'Disk (C:)',        default: true },
+  { id: 'lastresponse', label: 'Letzter Kontakt',  default: false },
+]
+
+const STORAGE_KEY = 'rmm-windows-columns'
+
+function loadColumns() {
+  try {
+    const saved = localStorage.getItem(STORAGE_KEY)
+    if (saved) return JSON.parse(saved)
+  } catch {}
+  return ALL_COLUMNS.filter(c => c.default).map(c => c.id)
 }
 
-function fmtUptime(s) {
-  if (!s) return '—'
-  const d = Math.floor(s / 86400)
-  const h = Math.floor((s % 86400) / 3600)
-  return d > 0 ? `${d}d ${h}h` : `${h}h`
+function saveColumns(cols) {
+  localStorage.setItem(STORAGE_KEY, JSON.stringify(cols))
 }
 
-function fmtBytes(b) {
-  if (!b) return '—'
-  if (b >= 1073741824) return `${(b / 1073741824).toFixed(1)} GB`
-  return `${(b / 1048576).toFixed(0)} MB`
+function formatUptime(seconds) {
+  if (!seconds) return '—'
+  const d = Math.floor(seconds / 86400)
+  const h = Math.floor((seconds % 86400) / 3600)
+  const m = Math.floor((seconds % 3600) / 60)
+  if (d > 0) return `${d}d ${h}h`
+  return `${h}h ${m}m`
 }
 
 export default function Windows() {
-  const [agents, setAgents]         = useState([])
-  const [customers, setCustomers]   = useState([])
-  const [details, setDetails]       = useState({})
-  const [search, setSearch]         = useState('')
-  const [selectedId, setSelectedId] = useState(null)
-  const [loading, setLoading]       = useState(true)
+  const [agents, setAgents]           = useState([])
+  const [customers, setCustomers]     = useState([])
+  const [agentDetails, setAgentDetails] = useState({})
+  const [search, setSearch]           = useState('')
+  const [loading, setLoading]         = useState(true)
+  const [sortKey, setSortKey]         = useState('customer')
+  const [sortDir, setSortDir]         = useState('asc')
+  const [selectedId, setSelectedId]   = useState(null)
+  const [visibleCols, setVisibleCols] = useState(loadColumns)
+  const [showColMenu, setShowColMenu] = useState(false)
+  const colMenuRef = useRef(null)
 
   const reload = () => {
-    Promise.all([api.getAgents(), api.getCustomers()]).then(([a, c]) => {
-      const win = a.filter(ag => ag.platform === 'windows')
-      setAgents(win)
-      setCustomers(c)
-      setLoading(false)
-      win.forEach(ag => {
-        api.getAgent(ag.id).then(d => setDetails(prev => ({ ...prev, [ag.id]: d })))
+    Promise.all([api.getAgents(), api.getCustomers()])
+      .then(([a, c]) => {
+        setAgents((a || []).filter(ag => ag.platform === 'windows'))
+        setCustomers(c || [])
       })
-    })
+      .finally(() => setLoading(false))
   }
 
-  useEffect(() => { reload() }, [])
+  useEffect(() => {
+    reload()
+    const iv = setInterval(reload, 30000)
+    return () => clearInterval(iv)
+  }, [])
+
+  useEffect(() => {
+    agents.forEach(a => {
+      if (!agentDetails[a.id]) {
+        api.getAgent(a.id).then(d =>
+          setAgentDetails(prev => ({ ...prev, [a.id]: d }))
+        )
+      }
+    })
+  }, [agents])
+
+  // Close column menu on click outside
+  useEffect(() => {
+    const handler = (e) => {
+      if (colMenuRef.current && !colMenuRef.current.contains(e.target)) setShowColMenu(false)
+    }
+    document.addEventListener('mousedown', handler)
+    return () => document.removeEventListener('mousedown', handler)
+  }, [])
 
   const customerMap = useMemo(() =>
-    Object.fromEntries(customers.map(c => [c.id, c])), [customers])
+    Object.fromEntries((customers || []).map(c => [c.id, c])), [customers])
 
-  const rows = useMemo(() => agents.map(a => {
-    const d   = details[a.id]
-    const sys = d?.system_data
-    const win = sys?.windows
+  const toggleSort = (key) => {
+    if (sortKey === key) setSortDir(d => d === 'asc' ? 'desc' : 'asc')
+    else { setSortKey(key); setSortDir('asc') }
+  }
+
+  const toggleCol = (id) => {
+    const col = ALL_COLUMNS.find(c => c.id === id)
+    if (col?.locked) return
+    const next = visibleCols.includes(id)
+      ? visibleCols.filter(c => c !== id)
+      : [...visibleCols, id]
+    setVisibleCols(next)
+    saveColumns(next)
+  }
+
+  const isColVisible = (id) => visibleCols.includes(id)
+
+  const enriched = useMemo(() => agents.map(a => {
+    const d    = agentDetails[a.id]
+    const win  = d?.system_data?.windows
     const cust = a.customer_id ? customerMap[a.customer_id] : null
-    const memUsed = win?.memory?.total_bytes > 0
-      ? ((win.memory.total_bytes - win.memory.available_bytes) / win.memory.total_bytes * 100)
+
+    const memPct = win?.memory?.total_bytes > 0
+      ? ((win.memory.total_bytes - (win.memory.available_bytes ?? 0)) / win.memory.total_bytes * 100)
       : null
+
+    // Ersten FIXED-Disk nehmen (meistens C:)
     const disk = win?.disks?.[0]
+    const diskPct = disk?.used_percent ?? null
+
     return {
-      id: a.id, name: a.name, status: a.status,
-      version: a.agent_version,
-      customer: cust ? `${cust.number} — ${cust.name}` : '—',
-      customer_id: a.customer_id,
-      os: win?.os_version?.replace('Windows ', 'Win ') || '—',
-      cpu: win?.cpu?.load_percent != null ? fmtPct(win.cpu.load_percent) : '—',
-      ram: memUsed != null ? fmtPct(memUsed) : '—',
-      disk: disk?.used_percent != null ? fmtPct(disk.used_percent) : '—',
-      uptime: fmtUptime(win?.uptime_seconds),
-      lastHB: a.last_heartbeat
-        ? new Date(a.last_heartbeat).toLocaleString('de-DE', { day: '2-digit', month: '2-digit', hour: '2-digit', minute: '2-digit' })
-        : '—',
+      ...a,
+      customer: cust,
+      customerName: cust?.name || '',
+      customerNumber: cust?.number || '',
+      os: win?.os_version || '—',
+      cpuPct: win?.cpu?.load_percent ?? null,
+      memPct,
+      diskPct,
+      uptime: win?.uptime_seconds || 0,
     }
-  }), [agents, details, customerMap])
+  }), [agents, agentDetails, customerMap])
 
   const filtered = useMemo(() => {
-    if (!search) return rows
-    const q = search.toLowerCase()
-    return rows.filter(r =>
-      r.name.toLowerCase().includes(q) ||
-      r.customer.toLowerCase().includes(q) ||
-      r.os.toLowerCase().includes(q)
-    )
-  }, [rows, search])
+    let list = enriched
+    if (search) {
+      const q = search.toLowerCase()
+      list = list.filter(a =>
+        a.name.toLowerCase().includes(q) ||
+        (a.ip || '').toLowerCase().includes(q) ||
+        (a.hostname || '').toLowerCase().includes(q) ||
+        a.customerName.toLowerCase().includes(q) ||
+        a.customerNumber.toLowerCase().includes(q)
+      )
+    }
+    list = [...list].sort((a, b) => {
+      let va, vb
+      switch (sortKey) {
+        case 'customer': va = a.customerNumber; vb = b.customerNumber; break
+        case 'name':     va = a.name;           vb = b.name;           break
+        case 'os':       va = a.os;             vb = b.os;             break
+        case 'version':  va = a.agent_version || ''; vb = b.agent_version || ''; break
+        case 'uptime':   return sortDir === 'asc' ? a.uptime - b.uptime : b.uptime - a.uptime
+        case 'cpu':      return sortDir === 'asc' ? (a.cpuPct ?? 999) - (b.cpuPct ?? 999) : (b.cpuPct ?? -1) - (a.cpuPct ?? -1)
+        case 'ram':      return sortDir === 'asc' ? (a.memPct ?? 999) - (b.memPct ?? 999) : (b.memPct ?? -1) - (a.memPct ?? -1)
+        case 'disk':     return sortDir === 'asc' ? (a.diskPct ?? 999) - (b.diskPct ?? 999) : (b.diskPct ?? -1) - (a.diskPct ?? -1)
+        case 'status':   va = a.status; vb = b.status; break
+        default:         va = a.name; vb = b.name
+      }
+      if (typeof va === 'string') {
+        const cmp = va.localeCompare(vb)
+        return sortDir === 'asc' ? cmp : -cmp
+      }
+      return 0
+    })
+    return list
+  }, [enriched, search, sortKey, sortDir])
 
-  if (loading) return <div className="p-6 text-gray-500">Laden...</div>
+  const SortHeader = ({ label, k, className = '' }) => (
+    <th
+      className={`px-3 py-2 font-medium cursor-pointer hover:text-gray-300 select-none ${className}`}
+      onClick={() => toggleSort(k)}
+    >
+      <span className="inline-flex items-center gap-1">
+        {label}
+        {sortKey === k && (sortDir === 'asc'
+          ? <ChevronUp className="w-3 h-3" />
+          : <ChevronDown className="w-3 h-3" />
+        )}
+      </span>
+    </th>
+  )
 
   return (
-    <div className="flex flex-col h-full">
-      {/* Toolbar */}
-      <div className="flex items-center gap-3 px-6 py-3 border-b border-gray-800">
-        <Monitor className="w-4 h-4 text-sky-400" />
-        <span className="text-sm font-medium text-white">Windows Agents</span>
-        <span className="text-xs text-gray-500">({agents.length})</span>
-        <div className="flex-1" />
-        <div className="relative">
-          <Search className="absolute left-2.5 top-2 w-3.5 h-3.5 text-gray-500" />
+    <div className="space-y-4">
+      <div className="flex items-center justify-between">
+        <h1 className="text-xl font-bold text-white">Windows Agents ({agents.length})</h1>
+      </div>
+
+      <div className="flex items-center gap-3">
+        <div className="relative flex-1">
+          <Search className="absolute left-3 top-2.5 w-4 h-4 text-gray-500" />
           <input
-            value={search} onChange={e => setSearch(e.target.value)}
-            placeholder="Suchen..."
-            className="pl-8 pr-3 py-1.5 bg-gray-800 border border-gray-700 rounded text-sm text-white focus:outline-none focus:border-sky-500 w-56"
+            type="text"
+            placeholder="Suchen (Name, IP, Kunde)..."
+            value={search}
+            onChange={e => setSearch(e.target.value)}
+            className="w-full bg-gray-900 border border-gray-800 rounded pl-10 pr-3 py-2 text-sm text-white placeholder-gray-600 focus:outline-none focus:border-sky-500"
           />
         </div>
+        {/* Spalten-Toggle */}
+        <div className="relative" ref={colMenuRef}>
+          <button
+            onClick={() => setShowColMenu(!showColMenu)}
+            className="p-2 bg-gray-900 border border-gray-800 rounded hover:border-gray-600 text-gray-400 hover:text-white transition-colors"
+            title="Spalten konfigurieren"
+          >
+            <Settings2 className="w-4 h-4" />
+          </button>
+          {showColMenu && (
+            <div className="absolute right-0 top-full mt-1 z-50 bg-gray-900 border border-gray-700 rounded-lg shadow-xl py-2 w-52">
+              <div className="px-3 py-1 text-xs text-gray-500 font-medium">Sichtbare Spalten</div>
+              {ALL_COLUMNS.map(col => (
+                <label
+                  key={col.id}
+                  className={`flex items-center gap-2 px-3 py-1.5 text-sm cursor-pointer hover:bg-gray-800 ${col.locked ? 'opacity-50 cursor-not-allowed' : ''}`}
+                >
+                  <input
+                    type="checkbox"
+                    checked={visibleCols.includes(col.id)}
+                    onChange={() => toggleCol(col.id)}
+                    disabled={col.locked}
+                    className="rounded border-gray-600 bg-gray-800 text-sky-500 focus:ring-sky-500 focus:ring-offset-0"
+                  />
+                  <span className="text-gray-300">{col.label}</span>
+                </label>
+              ))}
+            </div>
+          )}
+        </div>
       </div>
 
-      {/* Tabelle */}
-      <div className="flex-1 overflow-auto">
-        {filtered.length === 0 ? (
-          <div className="p-8 text-center text-gray-500">
-            {agents.length === 0 ? 'Keine Windows Agents registriert' : 'Keine Ergebnisse'}
-          </div>
-        ) : (
-          <table className="w-full text-sm">
+      {loading ? (
+        <div className="text-gray-500">Laden...</div>
+      ) : (
+        <div className="bg-gray-900 rounded-lg border border-gray-800 overflow-x-auto">
+          <table className="w-full text-xs whitespace-nowrap">
             <thead>
-              <tr className="border-b border-gray-800 text-left">
-                {['Status', 'Name', 'Kunde', 'OS', 'Version', 'CPU', 'RAM', 'Disk', 'Uptime', 'Letzter Kontakt'].map(h => (
-                  <th key={h} className="px-4 py-2 text-xs text-gray-500 font-medium whitespace-nowrap">{h}</th>
-                ))}
+              <tr className="border-b border-gray-800 text-left text-gray-500 text-xs">
+                <th className="px-2 py-1.5 font-medium w-8"></th>
+                {isColVisible('customer')     && <SortHeader label="KUNDE"   k="customer" />}
+                {isColVisible('name')         && <SortHeader label="NAME"    k="name" />}
+                {isColVisible('hostname')     && <th className="px-3 py-2 font-medium">HOSTNAME</th>}
+                {isColVisible('os')           && <SortHeader label="OS"      k="os" />}
+                {isColVisible('version')      && <SortHeader label="AGENT"   k="version" />}
+                {isColVisible('ip')           && <th className="px-3 py-2 font-medium">IP</th>}
+                {isColVisible('uptime')       && <SortHeader label="UPTIME"  k="uptime" />}
+                {isColVisible('cpu')          && <SortHeader label="CPU"     k="cpu" />}
+                {isColVisible('ram')          && <SortHeader label="RAM"     k="ram" />}
+                {isColVisible('disk')         && <SortHeader label="DISK"    k="disk" />}
+                {isColVisible('lastresponse') && <th className="px-3 py-2 font-medium">LETZTER KONTAKT</th>}
               </tr>
             </thead>
-            <tbody className="divide-y divide-gray-800/50">
-              {filtered.map(r => (
+            <tbody className="divide-y divide-gray-800">
+              {filtered.map(a => (
                 <tr
-                  key={r.id}
-                  onClick={() => setSelectedId(r.id)}
-                  className={`hover:bg-gray-800/50 cursor-pointer transition-colors ${selectedId === r.id ? 'bg-gray-800/70' : ''}`}
+                  key={a.id}
+                  onClick={() => setSelectedId(a.id)}
+                  className={`hover:bg-gray-800/50 transition-colors cursor-pointer ${selectedId === a.id ? 'bg-gray-800/70' : ''}`}
                 >
-                  <td className="px-4 py-2">
-                    <StatusBadge status={r.status} size="dot" />
-                  </td>
-                  <td className="px-4 py-2 text-white font-medium whitespace-nowrap">{r.name}</td>
-                  <td className="px-4 py-2 text-gray-400 whitespace-nowrap text-xs">{r.customer}</td>
-                  <td className="px-4 py-2 text-gray-300 whitespace-nowrap text-xs">{r.os}</td>
-                  <td className="px-4 py-2 text-gray-500 text-xs font-mono">{r.version ? `v${r.version}` : '—'}</td>
-                  <td className="px-4 py-2 text-gray-300 text-xs">{r.cpu}</td>
-                  <td className="px-4 py-2 text-gray-300 text-xs">{r.ram}</td>
-                  <td className="px-4 py-2 text-gray-300 text-xs">{r.disk}</td>
-                  <td className="px-4 py-2 text-gray-500 text-xs">{r.uptime}</td>
-                  <td className="px-4 py-2 text-gray-600 text-xs whitespace-nowrap">{r.lastHB}</td>
+                  <td className="px-2 py-1.5"><StatusBadge status={a.status} size="dot" /></td>
+                  {isColVisible('customer') && (
+                    <td className="px-3 py-1.5 text-gray-400">
+                      {a.customer
+                        ? <span className="text-sky-400">{a.customerNumber}</span>
+                        : <span className="text-gray-600">—</span>}
+                    </td>
+                  )}
+                  {isColVisible('name')     && <td className="px-3 py-1.5 text-white font-medium">{a.name}</td>}
+                  {isColVisible('hostname') && <td className="px-3 py-1.5 text-gray-400">{a.hostname || '—'}</td>}
+                  {isColVisible('os')       && <td className="px-3 py-1.5 text-gray-400">{a.os}</td>}
+                  {isColVisible('version')  && <td className="px-3 py-1.5 text-gray-500">{a.agent_version ? `v${a.agent_version}` : '—'}</td>}
+                  {isColVisible('ip')       && <td className="px-3 py-1.5 text-gray-400">{a.ip || '—'}</td>}
+                  {isColVisible('uptime')   && <td className="px-3 py-1.5 text-gray-400">{formatUptime(a.uptime)}</td>}
+                  {isColVisible('cpu')      && <td className="px-3 py-1.5"><MiniBar value={a.cpuPct} /></td>}
+                  {isColVisible('ram')      && <td className="px-3 py-1.5"><MiniBar value={a.memPct} /></td>}
+                  {isColVisible('disk')     && <td className="px-3 py-1.5"><MiniBar value={a.diskPct} /></td>}
+                  {isColVisible('lastresponse') && (
+                    <td className="px-3 py-1.5 text-gray-500">
+                      {a.last_heartbeat ? new Date(a.last_heartbeat).toLocaleString('de-DE') : '—'}
+                    </td>
+                  )}
                 </tr>
               ))}
             </tbody>
           </table>
-        )}
-      </div>
+          {filtered.length === 0 && (
+            <div className="text-center py-8 text-gray-500">
+              {search ? 'Keine Treffer' : 'Keine Windows Agents registriert'}
+            </div>
+          )}
+        </div>
+      )}
 
-      {/* Panel */}
       {selectedId && (
         <WindowsPanel
           agentId={selectedId}
@@ -155,3 +306,16 @@ export default function Windows() {
     </div>
   )
 }
+
+function MiniBar({ value }) {
+  if (value === null || value === undefined) return <span className="text-gray-600 text-[10px]">—</span>
+  const color = value > 90 ? 'bg-red-500' : value > 70 ? 'bg-yellow-500' : value > 50 ? 'bg-blue-500' : 'bg-green-500'
+  return (
+    <div className="flex items-center gap-1">
+      <div className="w-10 h-1 bg-gray-800 rounded overflow-hidden">
+        <div className={`h-full rounded ${color}`} style={{ width: `${Math.min(value, 100)}%` }} />
+      </div>
+      <span className="text-[10px] text-gray-400">{value.toFixed(0)}%</span>
+    </div>
+  )
+}