If you are running one of the Microsoft NT based operating systems, NT, Windows 2000 or XP, you need to run this patch immediately, if you haven't already. There is another hole in MS operating systems that allow an intruder to exploit the RPC service. This will cause your system to act very strangely and compromise your system's security.
Go to this link and execute the patch for your operating system. I've already had 7 systems that I know of, infected in the last 4 days.