You could try dumping this into a standard module. Written for Word, but apparently works in Access as well.
Code:
Private Declare Sub keybd_event Lib "user32" (ByVal bVk As Byte, ByVal _
bScan As Byte, ByVal dwFlags As Long, ByVal dwExtraInfo As Long)
Private Const KEYEVENTF_KEYUP = &H2
Private Const VK_SNAPSHOT = &H2C
Private Const VK_MENU = &H12
Sub AltPrintScreen()
keybd_event VK_MENU, 0, 0, 0
keybd_event VK_SNAPSHOT, 0, 0, 0
keybd_event VK_SNAPSHOT, 0, KEYEVENTF_KEYUP, 0
keybd_event VK_MENU, 0, KEYEVENTF_KEYUP, 0
End Sub
Found it here http://word.mvps.org/faqs/macrosvba/PrtSc.htm