WIN32:Hupigon ONX[Trj]

[#1]

Is this a virus or a false positive ?
AVast flaggs this up in my Windows 7 backup files but not on my main disk.
There are numerous posts on the web about this but these range from false positive to a high risk trojan ?
Anyone any ideas.
Antimalwarebytes finds nothing.
Avast whilst flagging up the file just reports error finding file so it is not possible to move it to the chest or repair it ?
Using Windows 7 (everything is updated)

[#2]

A file that is flagged and not found usually means that something else has got to it first.  But that would only be the once, is this happening with repeated scans?
In any case, most antivirus programs avoid making the distinction between a file that contains a virus but is actually doing nothing and a virus that is actively running on your computer.  They do that in order to impress you with their hit rate, but actually the distinction is critical.  A virus in a backup isn't going to do you any harm unless you restore from that backup.