I am able to use my F keys and get into my OS with F12, but once I am in my OS my keyboard does not work. My mouse works and I have unplugged the system, but still no keyboard use.
Your BIOS is telling you the keyboard is not connected or is bad. Unplug the keyboard. If it is a PS2 keyboard check for bent pins and plug it back in. If it is a USB keyboard unplug and put it in another USB port. Usually USB ports are in pairs on the rear of the motherboard. If you have 4 ports then plug the connector into the other set or a front USB port. Reboot. If problem persists take the keyboard to another computer and test it. If it is a USB keyboard you can simply plug it in any open port. There is no need to reboot or unplug the other keyboard. If it is a PS2 keyboard you will have to shutdown and swap keyboards to test it.
