Radeon HD 3870 X2 problem

Hey everyone, im hoping someone here can help me. I have had this graphics card (Radeon HD 3870 X2) for 2 years now and i am starting to think that something is wrong. The card works wonderful with mid to higher graphic games, but when i run low end games it seems to crash my pc. I first noticed this with the game SPORE. I could play the game for 5-15 minutes and then it would freeze-up/crash the whole pc. I thought it was the games problem but after updates and things i finally figured out that if i ran the game in windowed mode it wouldn't crash. I discovered this happens when playing The Sims 2, Champions Online, and Diablo 2. When i play these in windowed mode they seem to play just fine. Then i just recently purchased The Sims Medieval and the game crashes as well after 2-5 mins. I play it in windowed mode and it seems to run for close to 30 mins then crash. Now im thinking its my graphics card thats acting up. I don't know if there are any settings i can change under the ATI CCCenter or what? I have previously updated the video drivers, but when i looked for updated drivers yesterday on the AMD site it takes me to the wrong drivers.I found out the hard way they're not the drivers I need. So im not sure if there are newer drivers or not either. Im hoping that my card isnt messed up and that maybe there is some simple things i can do to get it working.

Here is my current set-up:
OS: Vista Home Prem 64bit
MBoard: Asus P5k Deluxe Wifi-AP P35
GPU: Asus Radeon HD 3870 X2 1GB 512-bit GDDR3 PCI Express 2.0 x16
MEM: Adata 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400)
PSU: RAIDMAX Hybrid2 RX-730SS 730W
HD: Seagate 250G 7K 16M SATA2

If you have any questions ill gladly answer and i hope someone can help me

update to my last post: I did finally find the driver update for my card, and when i installed it i ended up in the same place as before. After the install and system restart i get a black screen, no signal to monitor. I have to use windows disk to do a system restore to fix it. So now im more confused because i realize that there is definitely a problem somewhere.