|do you have another dvd drive, either in this PC or another PC (even a friend's pc)? see if you can read the disk from another optical drive, even if the machine has insufficient hardware to RUN the game, at least you can determine if the issue is with the disk or the disk drive. I recommend this step first simply because it is faster and easier than trying to return the disk.|
if other drives can't read the disk either, then definitely contact the manufacturer. You MAY get lucky and be able to return to the distributor, which would be easier (like, it'd probably be easier to get Target or Best Buy to trade you copies of the game, rather than trying to get Blizzard to make the swap for you).