HP ZV5000 won't start up

Hi I have a hp ZV5000 laptop that was working fine my son was playing a flash game online then shut the comp off or hibernation (not exactly sure which he did) Now when you press the on key it starts the fans and such and I get the hp invent screen that allows you to go to the bios and such but then the screen goes blank. I read a few other posts about this problem but they all seemed to involve computers that were upgraded or worked on which mine has not been apart. The only thing I have replaced is the power supply but that was like a month ago and it still seems to power the comp up.I have tried the hard reset to no avail and there is a hdd test in the bios and I ran that and it was fine. Not really a computer guy but can fix some things. Thanks in advance for any help!