Option Explicit
Const HKEY_CLASSES_ROOT = &H80000000
Const REG_SZ = 1&
Const MAX_PATH = 260&
Private Declare Function RegDeleteKey Lib "advapi32.dll" Alias _
        "RegDeleteKeyA" (ByVal hKey As Long, ByVal lpSubKey As _
        String) As Long
 
Private Declare Function RegCloseKey Lib "advapi32.dll" ( _
        ByVal hKey As Long) As Long
 
Private RegRoot As Long
 
Private Sub Command1_Click()
Dim Result&
Result = RegKeyDelete(HKEY_CLASSES_ROOT, "TestSchlüssel")
End Sub
Private Function RegKeyDelete(Root&, Key$) As Long
  RegKeyDelete = RegDeleteKey(Root, Key)
End Function