Another idea would be to hit F8 as though you are going into safe mode and selecting "Last known good configuration..."
I'm not sure how far the pc goes into the boot process before the error message pops up, but it is worth a try.
When you turn the PC on, start tapping the F8 key in about one second intervals. With some luck you will get a black screen with white text with some options. Select the last known good configuration option. It should reboot and hopefully boot right into Windows.
If that doesn't work repeat the process and instead select "Safe mode". When the PC boots up there will be white text rolling against a black screen. Once that is done the screen will look cartoonish and have safe mode in all four corners, this is normal. Try running system restore while in safe mode (to a date prior to the problem) let it reboot and hopefully functionality will have returned.
mrmez not funny.