A new virus was unleashed yesterday – 5/1/2004. It's called the “sasser worm” and is incredibly damaging to your pc. As far as I know, this only infects Microsoft windows operating systems…mostly all OS of Microsoft.
You can go to the Microsoft website to download a “patch” to keep it out of your pc, and at the same time, have Microsoft run a “scan” of your hard drive to check if you've already been infected. They also have a simple way to clean out your hard drive, but please print it out before you start running anything.
Please take one second to at least run a check of your hard drive, then enable your firewall.