Hey guys, just to update you, this issue is now fixed, was a faulty graphics card.
The machine kept crashing during games.
On reboot the graphics would be really messed up and text would show similar to the image i posted above.
The onboard graphics work fine and so a new card has been put in.
The old card (9800gt) was hissing so I'm guessing the capacitors or something similar was on the way out.
Thanks for the replies