Cox Browser Alert - Potential Virus

Hello,

Since yesterday I have received a few times when opening my browser an alert from Cox that says:

Virus Alert
Cox has detected that an internet-connected device in your home may be infected with a virus.  

It then suggests you visit Cox's internet security page for virus removal options. Seeing as I only have one device connected to my modem, I did some scans with AVG (my real time anti-virus that scans every morning at 5am), Malwarebytes, RogueKiller, ComboFix, TDSSKiller, Norton Power Eraser, ZBot Killer, and a couple of other scanners that are designed to scan your master boot record, hidden file sectors, etc. yet nothing comes up. I also went through the trouble of reviewing all TCP/IP traffic and going through each process running.

If this very clean computer is the only device connected to my home network, why am I receiving this message? My computer isn't slow, my internet isn't slow, scans show absolutely nothing. I'm not a clueless computer user and I do have a background in IT (namely networking), but it irritates me that I'm receiving what I perceive to be false positives or advertisements from Cox about a virus that doesn't exist.