The repairing and reboot look can often come from a bad hard drive. You said it has a blank screen, so the screen is not working? Or are you talking about something else? The factory reset procedure you can find on HP support site for your model, but with a bad hard drive it won't work. You would need to use your restore disks and get a new hard drive. No restore disks, contact HP or use a base OEM Windows setup and activate with the Windows code on your laptop.