I have a Dell N4010 with 4GB RAM, ATI Radeon 54XX 1GB Graphic card, Windows 7 and Ubuntu 12.04 dual boot.
My laptop was working fine till morning, then I travelled to my office with the laptop in my bag. When I switched it on at office and logged into windows, after some time horizontally tilted blue and white lines appeared on the screen. Then the screen went black and the computer rebooted.
I thought its a one time problem, and rebooted again and again with strange patterns appearing on screen after a few minutes of usage. Mostly the patterns are white and blue lines.
It seemed my graphics driver could be a problem, so I tried booting into ubuntu. After a few minutes, the screen went colorful again (with colored squares appearing there). So probably it isn't a driver problem ?
I tried running the dell diagnostic utility and it found no problems.