Does the drive show up in the bios of the computer? If not, then you have a hardware failure of some sort.
To access the bios, you'll need to hit one of the function keys as you boot up. Unfortunately, HP uses different ones for different models, so look up your specific model, or read your manual. It should be F1, F10 or F11, though some use F2 or the Esc key.
Don't change anything in the bios, just hit the option to Exit and Discard changes.
One other thing to try is to go back to a restore point that was made prior to the start of the problem. But if it is a problem in hardware, this won't help.