any ideas what could cause my theater 550 pro to cause my system to hang like this? it's so random that i don't know when it's going to happen. sometimes it doesn't hange my system at all.

here are my system specs:

win xp pro sp2
2 seagate barracuda xms2 dominator 320gb hard drives
corsair 2 x 1gb 240-pin ddr2 sdram
intel core 2 duo e6600 conroe 2.4ghz
asus p5n32-e 680i nforce intel motherboard
xfx geforce 8800gtx xxx edition

i haven't used this card in over a year, but when i used it before i'd have zero problems with it. now it has this hanging problem. i haven't changed any hardware since i used it. the only thing i can think of is the newest driver i recently installed for it.

any ideas?