It's just like those hallway lights that just, one stops working. But with a laptop I try the following.

I take it apart and wiggle/reseat every connection. Some CPUs in some models would work loose, but that may not apply to your model.

If that doesn't help, remove the CDROM and try again. Then remove the hard disk and see if the screen comes on. Then unplug that RAM and try again.

Tell what happens.

bob