Option Explicit
 
'KERNEL32
Private Declare Function GetLogicalDriveStrings Lib "kernel32.dll" Alias _
  "GetLogicalDriveStringsA" (ByVal nBufferLength As Long, ByVal lpBuffer As _
  String) As Long
 
 
Private Sub Command1_Click()
  Dim sBuf As String, lRet As Long, I As Long
  Dim vDrives As Variant, sDrives As String, lDrives As Long
 
  sBuf = String(255, " ")
 
  lRet = GetLogicalDriveStrings(Len(sBuf), sBuf)
 
  If lRet > 0 Then lRet = lRet - 1
  sBuf = Left(sBuf, lRet)
 
  vDrives = Split(sBuf, vbNullChar)
  sDrives = Replace(sBuf, vbNullChar, " ")
  lDrives = UBound(vDrives) - LBound(vDrives) + 1
 
  MsgBox "Es gibt " & lDrives & " Laufwerk(e)" & vbNewLine & sDrives, _
    vbInformation
 
  If UBound(vDrives) >= LBound(vDrives) Then
    For I = LBound(vDrives) To UBound(vDrives)
      MsgBox vDrives(I), vbInformation
    Next I
  End If
 
End Sub

Viel Spass,
R@lf