Gaming How do you remap keys on a keyboard?

[Feels Good Man]

I have this button that I want to change to ctrl so I can crouch easier in games but I don't know how to. I can't bind that key to crouch for some reason so yeah, I cant do that.

I have Windows 7 Professional x64

 

[Jiggah]

What game? The keybinding should be in the game not in Windows.

 

[Feels Good Man]

All the games (L4D, HL2, CS:S, CS 1.6, Bioshock, etc.)

I found a way to remap that key to being ctrl though so I think it's good