If you installed the burning crusade during your free month of the original wow would you have to start paying

No because when you buy burning crusade it gives you another free month, same with Wrath of the Lich King, so it just adds another free month onto your already free month, so if you bought all three expansions then you would have 3 free months.

hey this is someone else than the above, i didnt get 1 month, it says im still frozen. it sucks. i bought BC and it upgraded but i didnt get 1 month :(