What's the error message that Counterstrike returns to you? If it roughly goes along the lines of "Unable to make connection", this means that's the server you connected to gave up on your connection because it took your computer too long to cache everything before entering the game.
Happens to make every time I join a new server, it shouldn't be too big a deal. Once I get disconnected, I just connect to the server again. My computer has still retained most of the cached information in memory, so I'm able to enter the game without trouble this time...my system specs are linked below. The problem is accounted to by my insufficient amount of RAM, I strongly suspect.