I can highly recommend the caps lock link given by Mac..
I've installed it on 2 computers, (One being a work computer, which was used by the same sort of d1ckhead described by Irish Steve), and never had a problem.
If you do decide to use it, make sure that you download and save the
"remove scancode mappings.reg" prog.
That way, when and if you want to get the PC back to normal, it only takes a couple of seconds to do.
When you've clicked on the link, you must restart your computer before it will have any effect.