try this function:
'判对注册表键是否存在
Public Function GetKey(KeyRoot As Long, KeyName As String) As Boolean
Dim lngReturnValue As Long ' 返回值
Dim hKey As Long ' 打开的注册键的句柄
'------------------------------------------------------------
' 打开根键 {HKEY_LOCAL_MACHINE...}
'------------------------------------------------------------
lngReturnValue = RegOpenKeyEx(KeyRoot, KeyName, 0, KEY_QUERY_VALUE, hKey) ' 打开一个注册键
If (lngReturnValue <> ERROR_SUCCESS) Then GoTo GetKeyError ' 句柄错...
GetKey = True ' 返回True
lngReturnValue = RegCloseKey(hKey) ' 关闭注册键
Exit Function ' 退出
GetKeyError: ' Cleanup After An Error Has Occured...
GetKey = False ' 返回False
lngReturnValue = RegCloseKey(hKey) ' 关闭注册键
End Function