Hi Crimpshrine, welcome to the forums!
Genie is right, resetting the CMOS clock will restore all your default BIOS settings. However, you shouldn't need to unplug the battery - as this can be irritatingly irritating
Near the battery, there should be a jumper with either 2 or 3 pins. If it's 2 pins...remove the jumper and turn the computer on and off around 5 times.
If it's 3 pins, move the jumper from the current 2 it's on, say it's on 1-2, move it to 2-3, and turn the compute ron and off around 5 times.
Once this has been done - replace the jumper to its original position and you should have access to your keyboard again.
Also, regarding your Windows installation problem - it could be a memory issue. Once we have your keyboard working again, we'll address that issue.