Mcdefender.exe is a process related to Internet Security fake antispyware (rogue security program). Without first stopping mcdefender.exe you will not be able to get rid of Internet Security malware and its annoing 'infected with W32/Blaster.Worm' popup alerts in the bottom-right section of your screen. Use the tips below that will explain how to kill mcdefender.exe running process and then effectively uninstall Internet Security scam.