cannot restart computer and will only shut down

[ProfessorU]

This means it's not a UPS problem. One down!

It might not even need a BIOS update, just a BIOS change. Of course, you should have the new drivers and firmware anyway, so it's a good idea to check the manufacturer's website.

There are several standards for power and power management features in computers. Most older motherboards like to keep the control, while the newer Windows OSes also want control. I would check your BIOS "power management" settings and try it on "ACPI" or disable it altogether. One or the other will probably work. Disabling it might cause you to lose functions like "standby", "sleep" and "hibernate" but the basics, like off and reset, should still work.