Be careful transfering the files to your external disk. The virus can follow if it's attached to the files.
If you already have files on that disk, they might get infected too. But this sounds like it's pretty much bound to be a new virus if 6 antivirus softwares aren't picking it up.
What if it isn't a virus after all? Maybe it's caused by some program bug or resource leak from something you're running. Perhaps a faulty system setting. I found this thread here that might suggest it being a bad driver:
http://www.sevenforums.com/network-shari...ernet.html
Actually, reading further it seems to be caused by McAfee NetGuard. Do you have that installed as one of your 6 antivirus softwares by any chance?