Trouble changing my Screensaver registries

I'm trying to lock the workstation after my program completes. This program runs on NT, so it is unable to use the LockWorkstation API. I am able to lock the workstation by using the send message api, but it does not work when the user has the screensaver of "None" selected.

I'm am trying to use the following code to change a screensaver of "None" to an active password protected screensaver I changed the registry and this seems to work when I refresh in Regedit. However, when I look in the control panel, the screen saver is still set to "None". Does anybody know why?

When the user changes the screensaver to "None" the SCRNSAVE.EXE registry disappears. Does it have something to do with creating a new registry and not an already existing one?

The sub Main is at the bottom:

Option Explicit

Public Const HKEY_CLASSES_ROOT = &H80000000
Public Const HKEY_CURRENT_USER = &H80000001
Public Const HKEY_LOCAL_MACHINE = &H80000002
Public Const HKEY_USERS = &H80000003
Public Const HKEY_PERFORMANCE_DATA = &H80000004
Public Const HKEY_CURRENT_CONFIG = &H80000005
Public Const HKEY_DYN_DATA = &H80000006
Public Const REG_SZ = 1 ' Unicode nul terminated string
Public Const REG_BINARY = 3 ' Free form binary
Public Const REG_DWORD = 4 ' 32-bit number
Public Const ERROR_SUCCESS = 0&

Public Declare Function RegOpenKey Lib "advapi32.dll" Alias "RegOpenKeyA" (ByVal hKey As Long, ByVal lpSubKey As String, phkResult As Long) As Long
Public Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long) As Long
Public Declare Function RegCreateKey Lib "advapi32.dll" Alias "RegCreateKeyA" (ByVal hKey As Long, ByVal lpSubKey As String, phkResult As Long) As Long
Public Declare Function RegDeleteKey Lib "advapi32.dll" Alias "RegDeleteKeyA" (ByVal hKey As Long, ByVal lpSubKey As String) As Long
Public Declare Function RegDeleteValue Lib "advapi32.dll" Alias "RegDeleteValueA" (ByVal hKey As Long, ByVal lpValueName As String) As Long
'--------------------------------------------------
Public Declare Function RegEnumKey Lib "advapi32.dll" Alias "RegEnumKeyA" (ByVal hKey As Long, ByVal dwIndex As Long, ByVal lpName As String, ByVal cbName As Long) As Long
Public Declare Function RegEnumValue Lib "advapi32.dll" Alias "RegEnumValueA" (ByVal hKey As Long, ByVal dwIndex As Long, ByVal lpValueName As String, lpcbValueName As Long, lpReserved As Long, lpType As Long, lpData As Byte, lpcbData As Long) As Long
'--------------------------------------------------
Public Declare Function RegQueryValueEx Lib "advapi32.dll" Alias "RegQueryValueExA" (ByVal hKey As Long, ByVal lpValueName As String, ByVal lpReserved As Long, lpType As Long, lpData As Any, lpcbData As Long) As Long
Public Declare Function RegSetValueEx Lib "advapi32.dll" Alias "RegSetValueExA" (ByVal hKey As Long, ByVal lpValueName As String, ByVal Reserved As Long, ByVal dwType As Long, lpData As Any, ByVal cbData As Long) As Long

Public Sub CreateKey(hKey As Long, strPath As String)
Dim hCurKey As Long
Dim lRegResult As Long

lRegResult = RegCreateKey(hKey, strPath, hCurKey)

If lRegResult <> ERROR_SUCCESS Then
' there is a problem
End If

lRegResult = RegCloseKey(hCurKey)

End Sub


Public Sub SaveSettingString(hKey As Long, strPath As String, strValue As String, strData As String)
Dim hCurKey As Long
Dim lRegResult As Long

lRegResult = RegCreateKey(hKey, strPath, hCurKey)

lRegResult = RegSetValueEx(hCurKey, strValue, 0, REG_SZ, ByVal strData, Len(strData))

If lRegResult <> ERROR_SUCCESS Then
'there is a problem
End If

lRegResult = RegCloseKey(hCurKey)
End Sub


Public Sub SaveSettingLong(ByVal hKey As Long, ByVal strPath As String, ByVal strValue As String, ByVal lData As Long)
Dim hCurKey As Long
Dim lRegResult As Long

lRegResult = RegCreateKey(hKey, strPath, hCurKey)

lRegResult = RegSetValueEx(hCurKey, strValue, 0&, REG_DWORD, lData, 4)

If lRegResult <> ERROR_SUCCESS Then
'there is a problem
End If

lRegResult = RegCloseKey(hCurKey)
End Sub


Public Sub SaveSettingByte(ByVal hKey As Long, ByVal strPath As String, ByVal strValueName As String, byData() As Byte)
' Make sure that the array starts with element 0 before passing it!
' (otherwise it will not be saved!)

Dim lRegResult As Long
Dim hCurKey As Long

lRegResult = RegCreateKey(hKey, strPath, hCurKey)

' Pass the first array element and length of array
lRegResult = RegSetValueEx(hCurKey, strValueName, 0&, REG_BINARY, byData(0), UBound(byData()) + 1)

lRegResult = RegCloseKey(hCurKey)

End Sub



Sub main()

SaveSettingString HKEY_CURRENT_USER, "Control Panel\Desktop", "SCRNSAVE.EXE", "C:\WINNT4.00\System32\ssmyst.scr"
SaveSettingString HKEY_CURRENT_USER, "Control Panel\Desktop", "ScreenSaveActive", "1"
SaveSettingString HKEY_CURRENT_USER, "Control Panel\Desktop", "ScreenSaverIsSecure", "1"
SaveSettingString HKEY_CURRENT_USER, "Control Panel\Desktop", "ScreenSaveTimeOut", "900"

MsgBox "Done"

End Sub