Activate A Product on Steam

[MrHat]

How exactly does this work?

I have my Civ 4 disc laying around, but can't find the installation disc.  If I have the cd-key, can I register it on Steam, then DL the client?

[NiX]

Theoretically that's how it should work. Though I have no idea if it's retro for non-Valve games.

[schild]

What is a CD key and where can I find it?

The CD Key is a serial number with a combination of 13, 18, or 25 letters and numbers - it can be found on a sticker inside your game's case or printed on the game's quick reference card.

The CD Key acts as your proof of purchase for the game - Steam Support may ask for it if you need to establish your ownership of an account. It is recommended that you keep your CD Key in a safe place to ensure the security of your account.
Which retail CD Keys are accepted on Steam?

All retail Valve games and a number of third-party games can be registered to your Steam account. All of the following games can be registered through Steam.

    * Valve CD Keys in this format: ####-#####-####
    * Valve CD Keys in this format: 1AB2C-D3FGH-456I7-JK8LM-NOP9Q
    * Dark Messiah CD Keys in this format: 1AB2C-D3FGH-456I7-JK8LM-NOP9Q
    * GTI Racing CD Keys in this format: 1AB2C-D3FGH-456I7-JK8LM-NOP9Q
    * Lost Planet: Extreme Conditions CD-keys in this format: 1AB2C-D3FGH-456I7-JK8LM-NOP9Q
    * Prey CD Keys in this format: AAB1BB2C345CDD6E E7
    * RACE - the WTCC Game CD Keys in this format: 1AB2C-D3FGH-456I7-JK8LM-NOP9Q
    * RACE 07 CD Keys in this format: 1AB2C-D3FGH-456I7-JK8LM-NOP9Q
    * Ragdoll Kung Fu CD Keys in this format: 1AB2C-D3FGH-456I7-JK8LM-NOP9Q
    * Red Orchestra CD Keys in this format: 1AB2C-D3FGH-456I7-JK8LM-NOP9Q
    * SiN Episodes: Emergence CD Keys in this format: 1AB2C-D3FGH-456I7-JK8LM-NOP9Q
    * The Ship CD Keys in this format: 1AB2C-D3FGH-456I7-JK8LM-NOP9Q

http://support.steampowered.com/cgi-bin/steampowered.cfg/php/enduser/std_adp.php?p_faqid=68

[MrHat]

Damnit.