First, is your laptop under warranty?
If it is, contact HP via the support site and request an RMA.
If it is not, I would like you to read through and follow the outlines in the Black Screen Issues and Troubleshooting thread
. This will require taking your laptop apart, so be sure you are comfortable with doing that.
Here is a link to the Service/Maintenance guide for your laptop. It will give you the information you need to help disassemble your laptop and reassemble it successfully.
Good luck and post back the results.