I'm experiencing similar problems on my Macbook Pro (8600M) when using Boot Camp to run Windows XP natively. Here's what I've noted
- Sometimes when Windows loads, it finishes displaying the Windows logo and loading bar, and then stops with a black screen instead of displaying the desktop/login window. The computer continues to run, it appears to be a graphics problem
- Booting into safe mode works fine
- Uninstalling the 8600M from device manager in safe mode, and then booting into Windows normally and reinstalling the driver appears to temporarily fix the problem, so it runs normally for a while afterwards
that the problem is caused because I sometimes use a 22" external monitor over DVI. If the computer is shut down with the monitor plugged in, and then attempted to start with with the monitor unplugged, I get the black screen problem. Similarly, if I shut it down without the external monitor and start it up with the monitor, black screen again. So to fix things, try booting into safe mode, uninstalling the driver, then restarting normally and installing the driver again, then restarting without changing the display configuration.
And another thing, I've also had strange backlight and resolution problems, such as incorrect aspect ratios, random dim backlight etc. The fix for this is to disable all power management features in the Nvidia control panel.
For reference, I'm using 174.93 at the moment, I'll be upgrading shortly to see if that fixes things