Lol. I laugh with Rune. Wonder how many statements simply make no sense, let alone are impossible.
I linked my ip - makes no sense
I linked my ip to theirs that - makes no sense
i can put a proxie as his ip - impossible (you can't simply pick what your ip is; most ip's don't offer proxy services)
[if you have their ip] you have all the files he does - unlikely (local files have next to little to deal with ip, the target would need to be running running an HTTP/FTP/RDP/etc server, very unlikely)
you can delete all they fucking have - assuming you gained access via HTTP/FTP, your access is most likely limited (as a view-only mode)
including their cd keys - makes no sense (cd keys aren't files, they are strings of characters. How do you delete a physical object?)
just delete wc3 - assuming it is installed in Program Files and UAC is enabled, chances are you'd need their password as well
hack their battle.net - makes no sense, "battle.net" is a network that Blizzard owns, no on else. Perhaps their b.net account (assuming they have one)?
delete that account - impossible, you'd need to hack battle.net (see above), not any specific user. Have you ever seen a "DELte My ACCOunT" option?
incase they registered he'll never play again - assuming all access to keys are lost (physical object deleted an all), he can simply purchase one for $5
To anyone with even a first-grader knowledge of technology, you sound very, very silly.