The BIOS is what controls certain components, and conrols how things work on the machine at a hardware level. If it works in there, then it may be an issues withing Windows.
Try the "one time boot men" instead. As soon as you turn on the machine, keep tapping the F12 key to see if it goes there. If successful, you will get a list of devices listed. Simply use the up and down arrow keys to see if your keyboard works there. If it even gets into it is a sign of it working. Then shut down the machine.
Do you have an external keyboard that you can use to see if it behaves the same way?