Quite the Kerfuffle! What's wrong with my laptop?

Well, something that is baffling me is my laptop. A dell of 2 years was working fine until one day the screen randomly distorts. I ruled out lcd, because gently massaging the screen did not change the distortion patterns, thats not the weird part. When restarted the distortions seem to stop, few hours later they start again. So I reformat the dell, and it seems to stop for a couple of days, then out of no where slight distortions appear. the distortions look like pink rings around the windows basic background theme and pink lines appear on the start menu. about 8/10s of the middle of the task bar becomes lighter and the whole screen shows weird patterns depending on the picture! It is currently working fine, but I KNOW it will start up again! Any ideas?