Attribute VB_Name = "ChangeRes"
Option Explicit
Private Const CDS_UPDATEREGISTRY As Long = &H1
Private Const CCDEVICENAME As Long = &H20
Private Const CCFORMNAME As Long = &H20
Private Const DM_PELSHEIGHT As Long = &H100000
Private Const DM_PELSWIDTH As Long = &H80000
Private Const HWND_BROADCAST As Long = &HFFFF
Private Const WM_DISPLAYCHANGE As Long = &H7E
Private Declare Function ChangeDisplaySettings Lib "User32" Alias "ChangeDisplaySettingsA" (lpNewScreen As Any, ByVal dwFlags As Long) As Long
Private Declare Function EnumDisplaySettings Lib "User32" Alias "EnumDisplaySettingsA" (ByVal lpszDeviceName As Long, ByVal iModeNum As Long, lpNewScreen As Any) As Boolean
Private Declare Function SendMessage Lib "User32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Type NewScreen
    dmDeviceName As String * CCDEVICENAME
    dmSpecVersion As Integer
    dmDriverVersion As Integer
    dmSize As Integer
    dmDriverExtra As Integer
    dmFields As Long
    dmOrientation As Integer
    dmPaperSize As Integer
    dmPaperLength As Integer
    dmPaperWidth As Integer
    dmScale As Integer
    dmCopies As Integer
    dmDefaultSource As Integer
    dmPrintQuality As Integer
    dmColor As Integer
    dmDuplex As Integer
    dmYResolution As Integer
    dmTTOption As Integer
    dmCollate As Integer
    dmFormName As String * CCFORMNAME
    dmUnusedPadding As Integer
    dmBitsPerPel As Integer
    dmPelsWidth As Long
    dmPelsHeight As Long
    dmDisplayFlags As Long
    dmDisplayFrequency As Long
End Type
Public ScreenX As Long
Public ScreenY As Long

Private Function ChangeRes(X As Long, Y As Long) As Boolean
    Dim Screen_1024x768 As NewScreen
    EnumDisplaySettings 0&, 0&, Screen_1024x768
    Screen_1024x768.dmFields = DM_PELSWIDTH Or DM_PELSHEIGHT
    Screen_1024x768.dmPelsWidth = X
    Screen_1024x768.dmPelsHeight = Y
    ChangeDisplaySettings Screen_1024x768, &H4
    If ChangeDisplaySettings(Screen_1024x768, CDS_UPDATEREGISTRY) = 0 Then
        ChangeRes = True
    Else
        ChangeRes = False
    End If
    SendMessage HWND_BROADCAST, WM_DISPLAYCHANGE, 0&, (Y * 2 ^ 16 + X)
End Function