Private Declare Sub keybd_event Lib "user32" (ByVal bVk As Byte, ByVal bScan As Byte, ByVal dwFlags As Long, ByVal dwExtraInfo As Long)

Private Function Captura_Screen()
'On Error GoTo aki

Clipboard.Clear

'capturamos
keybd_event 44, 0, 0, 0
keybd_event 44, 0, KEYEVENTF_KEYUP, 0

'mientras no se pueda cojer el contenido
Do While Clipboard.GetData = False
DoEvents
Loop

Picture1.Picture = Clipboard.GetData
'borramos el portapapeles
Clipboard.Clear
SavePicture Picture1.Picture, "c:\sht.bmp"

Do While Len(Dir("c:\sht.bmp")) = 0
    DoEvents
Loop
'ya se ha guardado el archivo
End Function

Private Sub Form_Load()
Captura_Screen
End Sub