Graphics Card problem or does the root cause lie elsewhere?

[Baldrick1001]

PC has been running rather well, until a week ago when I experienced a lock up in CS Source. I have also had a couple of freezes with ni display on the screen, neccessitating a hard reset. The PC now seems to, randomly, "forget" the native set resolution when changing users - I have updated my bios and graphics driver, to no avail. Does this sound like a graphics card problem? I have had the card for around 16 months, fortunately it is a BFG so has a good warranty.

Any ideas or views much appreciated

Spec

Q6600 CPU
E45-U3DR MB
BFG 8800GTS 512
Corsair 620 HX
1 gig Samsung F1
500 Gig 7200.11

other odds and sods

 

[Baldrick1001]

you'll be disappointed to know that I have no overclock.... I have a coolermaster 631 mystique case, which despite looking good, isn't particularly good at ooling. that said, tower is pretty clean and the graphics card runs at rougly 75 c whilst gaming