I recently swapped over to windows 7 and would like to install warcraft 3 again. The problem is i lost my cds, but not the case with the keys on it. I tried copying over the game folder from xp but I get an error about writing files to my hard drive when I try to go on battle.net. Then I downloaded a torrent of the game and got the same problem, what can I do to fix it without a fresh install because I have no cds.
Not much you can do, I'm afraid, unless you can borrow the installation disk from a friend and and use your own key. Just copying the files across will not work. I suggest you completely remove everything, borrow a disk from someone, and start from scratch.
Go to www.battle.net and sign up for an account there. You can use the serial found on your CD Key to register your product with blizzard. From there you can download the game directly from blizzard, bypassing the need for your physical CDs.
You can add all of your blizzard games to this service, that way if you have scratched or lost CDs its no big deal.