Hi First:- Turn off the computer, press and hold the PWR button for 4 seconds.
Then - Leave only keyboard and mouse connected, disconnect all externally connected devices such as Docking Station, USB storage devices, displays, and printers. Unplug the AC adapter from the computer.
Next - Press and Hold the Power button for 15 seconds to Hard Reset. Rinse and Repeat
NOW begin checking/testing/proving the Hardware is fit for purpose.
Power on your PC, press ESC (repeatedly), then F2 at the prompt. Choose System Tests (Fast Test does a 4 minute hardware check). AND/OR HOW DO I USE DIAGNOSTICS?
HP PC Hardware Diagnostics Windows is a Windows-based utility that allows you to run diagnostic tests to determine if the computer hardware is functioning properly. The tool runs within the Windows operating system in order to diagnose hardware failures. HP PC Hardware Diagnostics Windows comes pre-installed on new HP computers, but if not on yours, download here:- http://ftp.hp.com/pub/softpaq/sp93001-93500/sp93457.exe
THE DIAGNOSTICS ARE TO CHECK IF THE HDD IS IN FACT WORKING.
Generating a 24 character error code, that you post here.
However the shortcut is to go and buy a new hard drive and re-install everything from your backups.