I have been out of the game for about 3 years, left during Cata. I played on a PC, now I have a Mac. I know I can re-roll my Subscription. I have Vanilla, BC, and Lich CD. I Downloded Cata Digitally. I am wondering if I can use all the same discs or do I need to purchase new one to begin playing again. CD Key reasons i guess is my question. I know I will have to purchase MoP. SO any help for a person contemplating returning would be appreciated. I just want to knowif I have to re-buy all discs or i am good with what I have. Thanks in advance.