Hmm... What do you mean by deleting all the executables? Anyways It also creates a MANIFEST file in the folder and has Microsoft in the file name.
Thanks for your help so far! Doing a virus scan right about now...
EDIT: I start having the error only when my brother goes to his acc and then back to mine. When I last had WoW before Cataclysm I used to come at night check my game (it was always corrupted), and reainstall it, I would then turn off my computer and tomorrw I would come back to play my favourite game. Everything worked fine, but when I get home from school(there is a 99.99999% that my brother was on it doing stuff) it's not working.
But, one morning i played a little, downloaded some file from the internet can't remember what, and BAM wow is corrupted