Laptop screen won't turn on

Hello,

The problem started yesterday, when using IE8, the laptop completely froze up (that is, I could still see the page I was reading, but the mouse cursor would not move, the built-in watch of the laptop would not advance, etc). This has happened before, and I was forced to turn off the laptop forcefully. Just FYI, when this happens, I am unable to turn the computer again for one hour or so, or otherwise after the loading screen nothing would show up.

Well, today, when I turned the laptop on, everything seemed to be right, but the mouse cursor would slow down when loading new pages in IE (or even when zooming in/out of Google Maps). So when I tried to load a game (which used to work fine), it said "Direct 3D not recognizable/missing" (don't quite remember the last words).

I turned off the computer, and an hour later tried to turn it on again, and the screen would be completely blank (no company logo, etc), and after waiting a few minutes, nothing on the laptop would apparently load. Tried again later without sucess.

The laptop in question is a Dell with one year of use and loads Windows Vista Ultimate. Thanks in advance for any input.