Believe to avast. What is your OS and avast version? You can try repairing avast: Windows 7 http://www.avast.com/faq.php?article=AVKB42#artTitle Windows 8: http://www.avast.com/faq.php?article=AVKB81#artTitle Windows XP: http://www.avast.com/faq.php?article=AVKB82#artTitle