[Battlefield 2] Battlefield 2 problem

First of all, I know this isn't the section for BF2 but I couldn't find it in the list. The problem is that I can join only 3 servers out of all other servers there. I have my filters on.

I bought Battlefield 2 Complete Collection and installed EVERYTHING that was on it (booster packs for BF2 and BF2 Special Forces). Then I found out that I need the patch 1.5 so OK I downloaded it and installed it (NOTE: I did not uninstall the booster packs or special forces). I tried going on a multiplayer server but it said 'Your CD key is invalid'

Please help I'm getting angry that I bought the game and it doesn't work properly