If your computer is affected by the
MSBlaster worm or
its variants; or your computer hasn't been patched against the worm, we urge you to patch your computer as soon as possible. You can find out how
on this page at Microsoft.
Also, it's highly advised you patch against
another security hole that's asking for trouble: There's a problem with DirectX that allows a virus, trojan, or any malicious programs to infect your computer by simply playing an infected MIDI file. This affects all DirectX versions from 5.2 all the way up to 9.0. Thus, you can be infected by simply viewing an email or webpage that has an auto-playing MIDI file. You can find out more and how to patch this
on this page at Microsoft. At least one other major media outlet
has reported this.
If you haven't installed all the critical updates in Windows Update, it's probably a good idea to do so now.