Correction, you still need the original cd (1 from stores) or it will give you a VALVe errorOriginally posted by Chrono Andrus
Correction, you can actually play online. You just have to find the right CD-Key. They are pretty rare nowadays.
That used to happen for almost every HL and CS player about 2 months ago when WON/VALVe was moving/updating their main server... it was a big problem for me and others until i read the official article @ cscentral.com, but its gone now, the only way i know how to get that error AGAIN (even if you bought the game) is to play HL or any of its of mods and quit them and try to play right away a few times, to fix all u need to do is restart ur computer.Originally posted by Muffsta***
that used to happen to me, but then it just stopped and it hasn't done it at all after that, don't ask me how i fixed it