PC Randomly Freezes When I Watch Videos/Play Games

[ecomog]

I built a PC the middle of last year, and ever since I've been having freezing problems. Either when I'm watching a video, or playing a game at random times my PC will completely freeze, forcing me to reboot. I've checked numerous threads and tried suggestions I've found there (testing different RAM, scanning for viruses, updating the bios/video card drivers, etc.) and so far nothing has worked.

At first I thought the card might be overheating, but even under a heavy load the highest temp it ever reached was 81 degrees (and that was only once while rendering an effects heavy video).

Any help anyone can provide would be greatly appreciated. I don't necessarily want to reinstall windows (especially since in some cases not even that worked for people), but I'll try that too if I have to.

Specs:

CPU: Intel Core i7-2600K Sandy Bridge 3.4GHz
Motherboard: ASUS P8Z68 DELUXE/GEN3 LGA 1155 Intel Z68
RAM: G Skill 1067.2 MHz (PC3-17000) 16GB
Graphics Card: HIS Radeon HD 6970
PSU: Antec High Current Gamer 900W

 

[Legaia]

I've had a similar problem before. I have to ask you where are hou doing the rendering and where are you keeping your games.

The issue I had was that as soon as I started to put some presure on my main drive such as making it load games or large amounts of data of some sort it would lag the computer out and I had to restart it. In due time this becamemore serious and ended up leading to bluescreens and later on I could barley even start the computer.
Had to bring the disc in to the retailer and they had to check it. The told me that there where some issues with the S-ata connection and they gave me a new harddrive.

 

[AstaLaVista]

Have you tried taking your video card out and testing with onboard video only? that or with another card?

Have you also updated your audio drivers? What about your chipset or bios drivers? Fan/CPU temps?