I have a Sharp Actius AV18 laptop/notebook. Last night, all of a
sudden, my arrow keys stopped working.

This is what I've done to fix it:

1. Cleaned underneath the keyboard
2. Uninstalled/Reinstalled keyboard driver
3. Reformatting the hard drives using my recovery disks (did not work
because arrow keys are needed to select options)

So, the keys don't work in Windows and they don't work in the BIOS and
Reformat screens.

Did I somehow short-circuit them? What happened?