The screen on my laptop is grey can't see anything

Many possibilities. If your computer is actually booting, you may have a burned out backlight. You may have a broken connection between the computer and the display.

There may also be a software problem. You may have a driver that's not functioning correctly or your operating system may be corrupt.

Questions:

1. Do you see anything when the computer starts up? If you hit <ESC> do you see printing on the screen as the system boots?

2. Does the screen glow at all or is it totally black?

3. Do you hear any disk sounds as the system is booting?