One of the problems of these worms is that unless you patch the OS, they just come back (the very next day, the cat came back...) Sorry, the kids are playing that again and tomorrow, another Cat!
Rather than duplicate the removal instructions, here's the link:
http://securityresponse.symantec.com/avcenter/venc/data/w32.welchia.worm.html
Worth REPEATING is this passage:
"The DCOM RPC vulnerability (described in Microsoft Security Bulletin MS03-026) using TCP port 135. The worm specifically targets Windows XP machines using this exploit."
If you use the TCPIP security, you can block the reinfection from outside until you have the patches in place.
Bob
Thanks for the thorough and timely answer to my posting yesterday "Virus-or what?". I thought I'd give you a report card on the results. Adaware found 43 files, Spybot found 185, Housecall Identified Nachi.A virus, but could not access it, CWshredder didn't identify any (maybe all was clean by the time I ran it),Stinger found and deleted Nachi, and I used Webattack to remove a couple programs that really didn't need to run at start-up but had installed themselves that way. However...net pages are loading as slowly as ever (think 14.4K days) and CPU usage still is always 100%...even when nothing is running. Could I have a problem with IE? It frequently it tells me my home page cannot be found, and I have a terrible time getting to the CNET forum, getting the same page cannot be found message even once I'm on the CNET site. Today I got here by entering "CNET XP forum" into Google.

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