ok well i think i understand your problem
1. Get Steam
2. Install Half-Life, CS etc if you have them
3.Go on steam and get a account by clicking new member
4.Follow the steps and type in pin code at the back of computer
5. It should then look for your games and install them all onto your steam account!
That should do it but if you already did this and your saying that it used to work but it stopped working so you reformatted the comp etc then well thats a problem that Steam can solve!
http://steampowered.custhelp.com/cgi-bin/steampowered.cfg/php/enduser/entry.phpHope this helps Maverick!