Duplicate Name On Network

[Bumblebee Tuna]

I've been getting this error message on my PC whenever I boot it up. "Duplicate name exists on network." I have two PC's both connected to the same router. I've had it this way for a few years now, and haven't changed anything, and have not had this problem until now. I've taken one PC, and changed the name, and put it on a different workgroup name, and I'm still getting this error message. I don't know what else to try.

 

[Lorithad]

Do you have a wireless network? Maybe somebody else has started using it and just so happens to have the same computer name.
Unlikely, but possible.

 

[bla!!]

If the first 15 characters of the computer names are the same, you will get this error. NetBIOS will truncate the name to the first 15 characters (this is what is giving you the error).