Ok, so lets go thru the things you have tried:

1) Removed and re-installed the latest version of your graphics card drivers
2) Tried using Alt-Enter

What are we left with - well, as it's clearly a graphics issue maybe you want to try an older version of the gfx driver for starters. Then, remove and re-install DirectX. Next, try starting the games with your desktop at a slightly lower resolution...I would imagine you've got that beast ramped up to 2048x1536 or something

My highest res in properties is 1920x1200, the problem with changing that is that it resizes my window. I could not find any other driver for my ATI Mobility. I did uninstall/reinstall directx... I tried a couple different games and I get varying results but no full screen...
As you may have guessed the main purpose of this monster machine is gameing and this is frustrating me to no end.

Could you try and set your resolution to something like 1024*768 and just see whether you can then run the game in full screen.

From bad to worse. I disabled my video adapter and now I get a black screen just after the Windows splash screen. I see the HD light blink every now and then but it doesn't seem to be booting. I'm running the onboard Dell diagnostic tool to see if that will help. I don't get the option to boot to safe mode, can this be done via CD?

Did you tab F8 to get in to safemode when booting up?

I hit F8, nothing happened. The screen just proceeds to blank.

Hmmm..hold the f8 pressed or keep tapping f8 from the moment you start to re-boot and see what happends then.

Did you disable anything in the bios or just in windows?