This is not illegal and he was not asking if it was illegal. There may be some sort of copy protection. If there is, disk utility should alert you BEFORE it starts burning, so you will not lose a disc (which only costs a penny anyway😛 ). If you copy it, I've seen Starcraft be played over a network with only one serial. I'd assume Warcraft could do the same. You'll probably find instructions somewhere on Blizzard's website.