I just got an email from our TAM in Microsoft. It must be important because we don’t normally get mails like this from MS. They’re warning us that a worm called Conficker is rampant at the moment. You are vulnerable if you have not deployed the security update MS08-067. If you do get infected by Conficker or Banload then there is a fix.
That security patch was released in October 2008. See how important it is to perform your updates? Don’t blame MS if you get hit by this one. And yes, Linux and Mac have security updates too!