I have an HP PAVILION dv1000 with windows xp on it. The laptop starts up and goes through the boot up process fine. I see everything up until I get to the main start screen. It shows the background for maybe 5 seconds, and then goes to a white screen. I can still see and move the mouse on the screen, but can't see any icons or the background. What could be the cause of this? How could I fix it?