Im on Windows 7, and checked run as administrator on properties of the warrock shortcut. I would do a virus scan too. I have had a virus that wouldnt let me key up on ventrilo. I am sure stranger things have happened. . .
Run Windows update. Get the optional stuff. Then go to microsof*****m > security > PC SCANS > and run the free one care scan. Just to make sure its not something dumb like registry errors, and if there is a virus it should pick it up.
Avast is a good free Antivirus imo. I have no problem playing any game, and all I use is Avast and Windows7, and my computer is not that great.