|A slim chance but worth a try:|
Remove the battery and press the on button a couple of times. Then reinstall the battery and try booting it again.
Tap F8 key repeatedly after starting to access advanced boot options. If it comes up try any of these (in order if available):
Last Good Configuration
Safe Boot, then System Restore from there
Remove battery, open memory compartment and pop out the memory sticks, clean contacts on sticks with a clean soft pencil eraser, remove remains and pop in and out a couple of times. Replace cover and battery and try starting.
Open the hard drive access and unplug and plug in hard drive connector. Replace cover and battery and try again.
You have to be a little bit crazy to keep you from going insane.