Failed HDD, old CMOS battery, virus/malware damage and more.

BUT since it was running 10 and we know Windows users know to backup files you could pull out a Windows 10 install USB or DVD to boot and install Windows from scratch. If the hardware is good, it will install, then the drivers and it's back.

Be sure to backup the installed image to save the time of install next time.

---> OK, I wonder if the HP "system locked" is a BIOS message. Those are often only clearable by the PC maker. Hit hp.com and it's chat button to find out.