Crash issue with Sapphire AMD HD 7850 2GB OC Edition

[Rattlesnake]

Hi,
I recently bought a Sapphire AMD HD 7850 2GB OC Edition about 2 months back, I'm not sure if its the graphic card issue but it does not seem to handle a few games.

The rest of my config is:
Intel i5 3470 Processor
Gigabyte GA-H77D3H
4GBx2 Corsair Vengeance RAM
500gb Hard Drive
Corsair GS-600 PSU

I can run the following games on full HD, with high graphics.
FIFA 13
Call of Duty: Black Ops
Portal 2
Batman: Arkham Asylum and City
Crysis: Very Hig Crashes, High settings work fine.

The issue is with the following games:
Call of Duty: Modern Warfare 2, crashes usually when there are many explosions, nightvision etc.
Prototype: Crashes when there is alot of action happening everywhere.
Mafia 2: Crashes every 10-15 minutes at high graphics.

Now looking at my config i should eat these games up for breakfast but it is really irritating to see even after spending so much on this I'm facing this issue, can anyone please let me know what the issue is and how it can be resolved.
I have read very good reviews about the OC edition of my card, should i replace it?

 

[vaibhavs800]

Try reinstalling latest drivers.
If that doesnt work, reinstall whole os. Are you using genuine windows? If yes turn on automatic updates.
Else rma that gpu