so you own a cd that contains these games? if so is your steam cracked? if so then remove the crack install then reinstall the crack. or if you dont own the game ("borrowing from a friend") disc and wish to install it, apply a crack to steam (if you havent already) then install the game.. as far as i know that should work.. ive tested it with my copy of orange box on my blank acc after i already registered it to my main acc. it shouldnt ask for the cd key or anything just insert the disk, have a cracked steam open, and open the program on the disc (i.e. steam.exe or whatever the installer is named for that disc) and ask it to reinstall the selected game(s)
although i could be wrong.. thats just what i did