Alot of Firewalls/Antispyware crap can block exe files from executing, its likely this, or possible of a virus, you might want to try HiJackThis, and get a log generated and post it on the Hijack site. Another thing is try uninstalling it, make sure logged in as an Administrator acct, and reinstall it. Or depending what version of Windows you are running, right click the EXE file and see if there is a RUN AS ADMINISTRATOR or go under properties and go under the compatability tab and check the admin option.