Sounds like a virus of some sort.

The reason your anti-virus is not working is most likely you do not have a signature for that virus.

You see a virus is just a program, just like every other program on your computer. You cannot tell a virus from a program, but you can tell one program from another.

Once your anti-virus company finds a "program" they want to call a virus, they configure the anti-virus software with a definition for that "program". Now when you ran a scan, if that program is on your hard drive, it will find it and identify it as a virus.

Presently anti-virus companies are not overly concerned about P2P or any virus that might infect P2P programs. If you're into conspiracy theories, it could be suggested a big corporation is releasing these virus and paying the anti-virus companies to look the other way. More than likely though they just do not see the money in P2P virus definitions yet.

You can try and get your anti-virus company to include your virus in their definitions. I doubt whoever wrote the virus went out of their way to make it easy to uninstall, unless you know a lot about computers or the an anti-virus company makes a fix, you might have to reformat your hard drive to rid yourself of this virus.

I recommend you talk to your anti-virus company. This is how anti-virus companies work, they wait for a virus to be released and for someone to report it to them, they then include this virus into their definitions. No help for you if you are one of the first to be infected, but better than nothing.

DO NOT click anything with the extensions .exe .com or .bat that you are not 100% sure about. If you follow that rule you cannot be infected this way.