Please help

I wrote a code which should automaticly run but it does not work
The strange thing is that it works on some of the PCs in the office. I use
office 2003.
I have previous experiance with VBA and event handel procedures.
May be it is some options or propperies ...i dont know

The code is

Private Sub Worksheet_Activate()
msgbox("test")
End Sub


Regards
Teodor