massive infecting worm is destorying XP/2k machines,
The worm's name is msblast and it isn't fun.
In many cases the worm causes XP machines to start rebooting periodically with this error message:
This system is being shut down in 60 seconds by NT Authority/System
due to an interrupted Remote Procedure Call (RPC)

I highly recommand to anyone running winxp or 2k to read this site and see if they are infected with msblast: http://www.datafellows.com/v-descs/msblast.shtml

The worm is spread via internet.. even if you don't download anything you can get infected.
The worm tries to connect to port 135 and check if the connection is successful. It then uses one of many different DCOM exploits to infiltrate the host.