Wanna activate the game here but old cd-key?

[Landoro]

So I finally found my old box of BF2 and wanted to activate it on Steam but it complains that the cd-key is not valid, why?
Do I have to buy the steam version to play multiplayer or can I install it the old fashioned way (by putting in the CD!) and still play multiplayer?

[El Detpacko]

you can't use disk/DVD cdkeys to activate the game

[Shinumino]

Retail CD Keys:
https://support.steampowered.com/kb_article.php?ref=7480-wusf-3601&l=english

[Shinumino]

scroll down a little bit and you see how cd-keys works on steam

[-IGF-SueKrueger13]

You cannot activate the disc game on steam to have it as a steam game. You can only add it to your Library as a non-steam game, NOT activate it.

[Landoro]

Ok, thanks all.
So nexr uestion, can I play multiplayer with my old game or do I need the Steam version?

[El Detpacko]

you need steam version, yes