Hi i have been battling for a few days now... I installed vista ultimate x64 and its freezing quite often, randomly, even on the desktop with nothing open. first all the programs and windows freeze, then the taskbar, and finally the mouse after a few seconds. other times i have been browsing the net for a few hours with no trouble... even played call of duty 4 online for 2 hours fine. cant figure it out. when i installed vista i let it download drivers for all my hardware... I have previously had vista ultimate 64bit installed with no problems, no freezing, but changed back to xp because of an old ms office. now i want vista back but having these irritating problems. it seems to occasionally freeze in safe mode as well... so i thought maybe drivers..? so i made sure to download and install all the latest drivers from the respective manufacturers. still no go so please any advice???