Previously, I have used the following code (from a book) successfully. In my
current MDB, however, the call to FindWindow raises the error: "Sub or
Function not defined". I don't remember ever having to explicitly declare Win
API functions from within VB or VBA. Am I missing a reference?

Thanks!
--Al

Sub DetectExcel()

' Detects a running instance of Excel and registers it.

' pre-25/06/07.

   Const WM_USER = 1024
   Dim hwnd As Long
   
' If Excel is running this API call returns its handle.

   hwnd = FindWindow("XLMAIN", 0)
   If hwnd = 0 Then    ' 0 means Excel not running.
       Exit Sub
   Else
   ' Excel is running so use the SendMessage API
   ' function to enter it in the Running Object Table.
       SendMessage hwnd, WM_USER + 18, 0, 0
   End If

End Sub