Games put your CD-KEY through an algorythm to genereated a user ID. This ID can be found in an .ini file in your games program folder you can go in an edit it. Im not sure if this is how counter strike does it, but I know I've used this method for other games. Your just going to have to search through the .ini files in the games folder till you find the right field to edit. Use catution doing this and back up your files before editing them so you don't completely mess up your system. Use catuion as always.