Ahhh, the BSOD. Restart your computer and run a virus scan to see if it picks anything up. Make sure to update your anti-virus program first though.
After that download and run Spybot Search http://majorgeeks.com/download.php?det=2471
and Destroy and Ad-Aware SE Personal http://majorgeeks.com/download.php?det=506
If Ad-Aware and Spybot Search and Destroy pick up a lot of files, boot into safe mode (tap F2 or DEL as your booting up then select "Boot into safe mode" or something similar) and run Ad-Aware SE Personal again.
If this keeps up, the BSOD, you can always reformat
which isn't too hard but is kind of a pain because you have to back everything up and you might lose some data.