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.
hp 2000 notebook upgraded to w 10. been working fine. was running IE and message came up about system problem need to call to fix problem. just shut down but when restarted it would not startup. asked for admin password, entered and hp logo comes up and might just set there on that screen forever or ask again for password. enter wrong password will give error push return will give message system locked or something like that and cannot do anything.