Microsoft Patch Causing Blue Screen of Death
This beset a few people I know:
KB977165 (aka MS10-015) is causing some people to get the blue screen of death.
A solution for some, which did not work for me: http://www.krebsonsecurity.com/2010/02/new-patches-cause-bsod-for-some-windows-xp-users/
Edit: Microsoft has withdrawn the patch for now. Should be safe to update.