Veljkom, I had pirate version of HL 2 too (now I have the official Orange Box, I bought it in October in a shop), but I downloaded Steam and a patch called UndeadParch, which allows you to download every gam e from Steam free. But it was shit, every time I wantedto download a gam,e it said: Sorry, but our servers are too busy to handle your request.
But it allowed to download Gmod! Anyway, I can't multiplayer because it says: Disconnect: this steam account does not own this game. Shit. Anyway, I can play Singleplayer, and I1m very happy.