Computer freezes then screen turns on and off while playing video games.

Your card, sometimes when there is power or cooling issues during gaming this is typical of a failing card or sometimes psu. Is the audio normal when the monitor loses signal?

nforce is correct, also look into re-installing drivers. do you get a display or .dll file has stopped responding?

I noticed that you haven't listed your PSU. What wattage and more importantly what company is it? This usually happens when the GPU draws more power at one point in the game and the PSU is incappable to suffice for this fluctuation. Check to see if every power cord is well attached on the GPU and if the GPU is well inserted into the motherboard. Reinstall the drivers first, then check the hardware.

My advice would be to test your video card first to see if it's a heatsink issue, leave the computer open with a movie playing and look to see if it fails at some point (2 Hours should be enough). If it does, the problem seems to be a heatsink issue and you should probably return the graphic card. If not, run your game, wait until it crashes and check for the sound (audio) like nforce4 said. If there is a tick scratchy noise, means the whole system shut down and the problem is probably the PSU or a controller on the motherboard. If the sound continues for a few seconds, it's clearly the GPU and this time it will be hard to pinpoint the problem using only OSD commands. If you still have the warranty, if would suggest that you use your right and send back this demon of a card from whilst it came!

Thx for the help so far guys. My PSU is corsair tx750. The sound cuts for a second then starts again while the screen is still turning on and off. I have already tried reinstalling the drivers, checked all the connections to the card/mobo and the temps are normal. The problem only ever happens while playing games. The most annoying thing is that my friend and I built our pc's at the exact same time with identical components and his isn't doing this.

Edit* Just came up with an error that the "280.26 kernal stop working and then recovered" does anyone know what that means?

Is this what's happening to you : http://www.youtube.com/watch?v=MPy_OWpAOY4

Anyway, you might try to change the card preset in the nvidia menu--> power consomption to PERFORMANCE. Try again.
Did the card start behaving like this after the driver update? If it did, you might wanna reinstall the drivers that came with the card, it might help. Kernel 280.26 is the operating part of the driver program, it failed meaning the driver might be corrupted.
Tell me if the 2 tricks above solved the problem, if not, we'll have to use.... more drastic measures