Possibly. It's kind of a long explanation. Punkbuster has a serious incompatibility with a lot of common utilities like Rivatuner or any other GPU monitoring or tweaking software.
Uninstall Punkbuster and see if that solves your problem.
I think I know what was the problem: overheating. While I'm playing TF2 my computer goes up to 80º C. I'm going to buy a cooler and hopefully blue screens will stop. Thanks anyway man!