How do I change a keyboard key function?

I do not use my right Alt, and I would like to have a Underline key on that place.

Is there a way to configure my right Alt to be an underline character key?

update: using Windows 7

2 Answers

You should look into AutoHotkey. You can use that program to assign different functions to your keys or you can create your own keyboard shortcuts.

Check out Microsoft Keyboard Layout Creator. With that you can create you own keyboard layout and install it on you computer in control panel -> keyboard. You should be able to map Alt to what ever you want.