I always advised customers to press control + alt + delete which brings up the Windows Task Manager advised customers click on MSBLAST.EXE next your gonna wanna click end process. This will disable MSBLASTER.EXE (until you reboot your computer) go to symantec.com download the removal tool. Also have customers install the latest patch for their Operating System. I have customers who just sign up with our Internet Service Provider get online and be infected just minutes later. Its a nasty virus.