Please provide your full model number found on the bottom of the laptop or maybe in the battery bay.
From the description the fist suspicion is that the hard drive has died. If you are under warranty contact HP directly at 1-800-HP-INVENT. We are not a warranty center, just fellow end users who try to help others. If not under warranty post back. We have helped a lot of folks in your shoes get their laptops back up and running.