Debilitating unknown problem! Freezes system completely - With pics

Hi everyone!

I have been in contact with Blizzard and the shop I bought my computer through and they are both stumped.

I have a brand new and tested computer with specs that well exceed the minimum requirements.

I am running windows 7 and a GTS 250 - which everyone has told me is fine.

My error occurs in the menus, cinematics and game play. At a seemingly random time my system locks. The picture and sound is heavily distorted. The screen then goes black and the background music continues. I believe what happens to the picture is called 'artifact'.

Everything is unresponsive - I can only do a hard restart.

Everything is up to date. Everything has been tested by the store and me at home. I upgraded my power supply thinking perhaps the graphics card wasn't getting enough juice - brought it home and the same error occurred.

PLEASE HELP ME!

I have two pictures of the error - both in menu. I have reset the frame rate for the menu btw!

 

Bump!