I have downloaded and installed Nod32 v.5.0.94.0. So far I have not see what you describe. I did not, however, have an install of a previous anti-virus except for Windows Defender, which I turned off.
Could it be that Norton had effected your install so as to make it look infected? I am assuming you had no previous encounters with a virus.
If explorer.exe has been changed or compromised in some way, perhaps a system file check, which can be run from the recovery environment, if necessary,might replace it.