Conficker, also known as Downup, Downandup and Kido, is a computer worm that surfaced in October 2008 and targets the Microsoft Windows operating system. The worm exploits a known vulnerability in the Windows Server service used by Windows 2000, Windows XP, Windows Vista, Windows Server 2003, Windows Server 2008, Windows 7 Beta and Windows Server 2008 R2 Beta.
The worm will deliver a yet unknown payload on April 1st, since it has infect almost 30 million PC's the result can be devastating, you can prevent the virus from infecting by installing the Microsoft patch MS08-067
here
Download and run one of the removal tools if you think your system is infected.
Microsoft Malicious software Removal Tool
BitDefender
Kasperskey