Question:
I was wondering if it would be possible to create a program named root.exe that would:

1. Send a message to the offending IP telling them to dis-infect their system.
or
2. Stopping their web server.
or
3. Blowing up their system.
So you'd be replacing your root.exe? Nimda just wishes to affect these files, create admin shares, and propagate itself.

I think.....

1. no.
2. see above.
3. see above.

You could simply send them an email? how come you haven't done that?

These are just thoughts/comments...