of course it does, but what hes referring to is that you can split your mounted harddrive into partitions allowing you to format one part of the disk while the other one stays "intact", that way you can install wow on a partition together with all your important files (pictures, music etc.) and then when you format your harddrive you can choose not to format that particular partition you have wow installed on and then when you get ure windows back up and running just run it from the partition or copy it back to the other one you just formated.
hope i didnt make it more complicated than it already was for u
