A "blue screen" of death is almost always a reflection of driver issues. You may have them all up to date, but that doesn't mean that some of them don't play well together. The fix for this problem is purely based on your individual setup. What kind of video card are you using? Do you have 2 video outputs on your computer? Is the video card's cooling fan working and efficient? Are you running XP or Vista? If Vista, you REALLY need to take a closer look at EVERY driver installed and make dam sure it is compatible with Vista.
"Blue screens" can also pop up if CPU settings are configured wrong in BIOS, did you by any chance adjust anything in the BIOS? Maybe, try to boost the CPU timing or something? These are very sensitive settings and some CPU's are VERY picky about them.
Without knowing any details about your system, I would say to try the following and see what happens:
1 - Restart your computer and go into your BIOS (usually by hitting DEL or F2 or something during startup). Find the setting that sets the BIOS to "Default" settings. This will automatically configure every setting in there to "working" settings.
2 - If you have 2 video cards (one removable and one built-in), take out the removable one and use the built-in... see how things work from there.
3 - Re-seating the CPU can sometimes alleviate a LOT of headaches. On rare occasions, they have been known to mis-seat and not fully contact all pins completely (make sure the locking lever is all the way down).
4 - Re-seat the RAM, just pull each stick out, then put it right back in.
Do each of those separately to see if it makes a difference, this way you can narrow down the problem. Post back your results and answers to my questions above, and I'll try to help you solve your issue.
