Need help to setup so I can play BF2 again like back in 2005

Hey! 

Im wondering if there is anyone here who can help me to be able to play BF2 again like we did when it came out.

I have a CDKEY, I know I need to have BF2hub and the right patches ect, but when I did all that and tried to play an online game, i just got disconncted pretty fast and the game closed. And according to BF2Hub, it said I didnt have a CDKEY registerd. But the problem is, I have ZERO clue what to do haha. I have watched many diffrent YT videos of guides how to do it, but it never ends up working.

Thanks a lot in advance! // Pelle