I-Worm.HappyTime.a

Worm HappyTime spreads by e-mails in infected messages. In most cases such messages come without attachments, so the worm can infect a PC even if a user didn't executed any attachment. The worm uses the Microsoft Outlook mail client to distribute itself to other e-mail addresses. It also infects web files found in a PC. Several times per year it tries to remove all found executable files and dynamic libraries, so the infected PC may fail on next startup and some software may function unproperly.