Downadup (or Conficker) is a network worm that takes advantage of vulnerabilities in Windows to spread. Its removal is complicated by the fact that it blocks many known antivirus software and associated websites.
The worm itself is not new, it made its first appearance late November 2008, known under the names Conficker or Kido as well exploiting the vulnerability described in the Microsoft security bulletin MS08-067. After successful exploitation it used to install rogue security software on the infected machine.
Download and run the tools provided at bdtools.net to rid your computer or newtork of this e-threat.