Nachi.A spreads by attacking remote computers and exploits the vulnerability mentioned above to download a copy of itself to the compromised computer. In order to do this, Nachi.A incorporates its own TFTP (Trivial File Transfer Protocol) server.
Nachi.A can uninstall the worm Blaster, by ending its process and deleting the file carrying the worm.
If you have a Windows 2003/XP/2000/NT computer, it is highly recommendable to download the security patch from the Microsoft website. Click here to access the web page for downloading the patch.
Moreover, Nachi.A can use another exploit known as WebDAV. More information about this vulnerability and the corresponding patch are available here.