X-Box controller for windows

[Patrick's Dad]

I've just bought one of these thinking that I'll wait a while for a proper x-box and use my PC for games.
I'm crap with a keyboard and the x-box controller seemed like a good idea.
I've loaded the software on and my machines recognise it - but how do I get a game to see it? At the moment all I am allowed to do is use the mouse and keyboard.
Advance apologies for being conputer dense in case the answer is right in front of me!

Help please

[JonRB]

I think the game has to explicitly support it. Crysis does, for example.