I've just brought a Dell Inspiron 6400 at end of last month. Until now I've only used that on 5/6 occasions coz most of the time I am using my existing desktop.
However, with less than a month since I bought it, a problem came when I was using it 2 days ago. The monitor suddenly turns brightly white which everything on the screen can hardly be seen. I've tried changing the brightness/contrast settings but no use. I've also tried connecting an external monitor to the laptop and test but found no problem on my external one. So I gave Dell a call and explained the problem, and they said some parts might need to be replaced. More surprisingly, I found out later in other forums that the same problem has occured before on the same model with a few other users.