totally white? That's wierd. Have you made sure your monitor connections are secure? How is your monitor connected to your video card? DVI or VGA. If you are connecting via DVI could you try using a DVI to VGA adapter for your monitor or connect using the VGA connector instead and see if that resolves your problem.
Check your running processes, what are you running? Which video card/monitor are you using?
I'm just saying cause I've had problems with my DVI connections on certain systems but the result was the screen going black then never coming back unless I rebooted I found that using the VGA interface for the lcd monitor resolved my issue.
Also check your screensaver settings, change the screensaver to a non 3-d screensaver like mystify or ribbons. Sometimes the 3d screen savers bork up the video on windows xp/vista