When I boot my system, it freezes on the XP splash screen with the little green progress bar. This worries me because the same thing has happened before I upgraded to XP x64. It makes me think that it might be hardware related. The only programs that i had installed both times were speedfan, windows defender (a different version due to the 64 bit upgrade, of course), thunderbird, and firefox. Booting in safe mode doesn't help either. Any ideas?