VGA projector no longer works with windows 7

I recently upgraded the OS on my Dell Lattitude D630 laptop from XP to Windows 7. Now when I plug in my VGA projector it no longer displays my computer through the projector. Nothing happens when I press the Functin F8 (CRT/LCD) keys which used to switch my display from the laptop screen to the projector image (if it did not come up automatically). It's as if the projector was not connected at all or the function key is not working (although it does work with the brightness keys). I've tried 3 different projectors and the same thing happens with all 3 so it's not the projector or cables. I'm not sure if I have a Function F8 key issue or a VGA driver issue. There are no drivers listed for Windows 7 on the Dell website. Any help would be VERY much appreciated. I give presentations for a living and if I can't fix this quick I'll have to reload XP. I love 7 except for this one Major issue.