a program used to generate a CD Key for a game.

yeah i tried that, but it looks like steam downloaded all the keygens and uploaded the generated cd keys and denied them activation

They keep track of all of the cd keys used in steam, and probably keep a database of all of the "real" cd keys used in there retail copies(they would need to do that to keep from making duplicate cd keys in there copies.). So using a cd key generator generated key most likely wouldn't work, unless you were lucky enough to generate one that is both real and hasn't been used yet.

PLUS Steam keeps watch of keys used in WON.

dude you need a real cd key for every version of half-life retail... excluding opposing force
but like i downloaded the keygen, and when i tried to use the key it said it was invalid
but there were a few that claimed duplicate
and i had used this same keygen in the past for extra copies of half-life hehehe
so steam downloaded it and made those cd keys invalid, and if you really have the cd key from retail and it didn't work
you'd just contact steam with a picture and all that, so you could get the game