My account keeps getting locked.

Every day now for a week when I have attempted to log into WoW my account has been locked. I have poured over my computers, files, I've debugged, defraged and scanned for every conceivable bug, spyware, trojan, using multiple programs for each. I thought I was out in the clear yesterday when I did all of this again and spent about 6 hours doing all the scans. I try to log on this morning, and BAM locked again. I only log on from one computer, I have started using password I've never used before, no one else knows my account info, or even the user name to log in. I do not yet have an authenticator, that is in the mail. I do not use any kind of tunneling service, I think unless I misunderstand what that is. I have never had this problem before a week ago.

Please help as I'm running out of passwords! This is a real inconvenience especially since I'm not really playing atm, I'm just logging in really quick to check my mail, so it's currently taking me longer to get into the game than the amount of time I spend in it.