my problem its, i have Wow of the litch king expansion, and im trying to update to 4.0.6, but i dont know how to do it, it always update to 5.0.5, can anyone tell me the way to update it to only Cataclysm?
It doesn't matter which game version you have bought, you will always want to have the latest client. Just launch the game launcher and it will fix everything for you.
You will see the same people online that have bought all the expansions, even if you didn't get any of them. You will just not be able to use the features of the new expansions (for example, the level cap will be lower for you).