If you wish to do a short scan of a specific file try out using the context menu for the folder where the file resides, you will see the "scan now" after hovering over "Norton Internet Security" on your right click context menu when viewing any folder.
As you have already discovered this option does not show for a single file
I think you will find this method to be very fast and effective
Let us know if you need more help or if this is off the mark on your question
Well, as said in my 1st post, the Insight Network Scan didn't report anything. Though I knew there was a virus in it, so I proceeded by manual scan and only then the virus was detechted.
Somewhere else on the forum it is suggested that it is the "Insight Scan" which is then to be understood as the 'traditional scan' of a single file.
The worrying thing is that the Insight Scan did nót report any viruses on the single file. However, doing a manual scan (from the main menu), thén NIS reports a virus.
That's the thing I was puzzled about.
BTW: I cud even un-rar the infected file but NIS did not alarm me.
(Unrar to a folder named after the file)
NIS running pretty much default settings on Win7 x64.