Private Declare Function GetWindowsDirectory Lib "kernel32" Alias _
  "GetWindowsDirectoryA" ( _
   ByVal lpBuffer As String, _
   ByVal nSize As Long) As Long
 
Public Function GetSystemDrive()
  Dim S As String, Result As Long
  S = Space(255)
 
  Result = GetWindowsDirectory(S, Len(S))
  If Result > 0 Then GetSystemDrive = Left(S, 1)
 
End Function

Viel Spass,
R@lf