A tool is available to remove Blaster worm and Nachi worm infections from
computers that are running Windows 2000 or Windows XP http://support.microsoft.com/?kbid=833330
You have a virus , probably because you did not use the firewall before
connecting to the internet. Use the search function (searching for "rpc" )
within the newsgroup and find many explanations and solutions . Jym
If you connected the PC to the Internet without having first
installed the KB824146 Hotfix, without having first installed an
antivirus application with current virus definition files, and before
enabling a firewall, you're very likely to get infected from any of
the thousands of PCs on the Internet that are constantly broadcasting
the Blaster and/or Welchia worms. It only takes a few seconds of
exposure.
To stay on-line long enough to get the necessary updates, patches,
and removal tools, click Start > Run, and enter "shutdown -a" when the
next RPC countdown begins. This will abort the shut down. Also, make
sure you've enabled a firewall before starting, to preclude any more
intrusions while getting the updates/patches/tools.