So, it powered down/crashed and any attempts to power it back up and load the O/S have been less than fruitful?
Does powering it up (It does still power up right? lol) result in simply a black screen with no messages/symbols/anything appearing at any time at all?
For starters, try taking the battery out and unplug it for 5-10 minutes, then plug the battery back in and plug it back into the wall (Doubt it'll work but it has in the past) Also, heres the link for the service manual:
http/h10032.www1.hp.com/ctg/Manual/c01740724.pdf
Edit: After you take the battery out/unplug it, hold the power button down for 15-20 seconds as well, http
/h10025.www1.hp.com/ewfrf/wc/document?docname=c01997899&tmp_task=solveCategory&lc=en&dlc=en&cc=us&product=4033875