Quietman and John, thank you both very much indeed. This seems like a great forum and you have both been really helpful to me, thanks
I will take both your suggestions and use both Clamwin and Virustotal
From what I can see, they both seem like excellent resources!
Having said this, what John said about behavior detection is interesting. I hadn't thought that some AV programs work that way: analyzing how other programs are actually behaving. So now I'm thinking maybe it might not hurt to install Avira for a few days while I am trying out new software, then uninstall it later.
(I couldn't leave Avira installed for long, as it pops up nag adverts which would drive me insane. Also I wouldn't use Avast, AVG, Zonealarm or Comodo because I have had terrible experiences with each of them in the past and don't trust them at all. I can go into more detail if anyone wishes.)
Edited by Ghostbusters2, 03 December 2016 - 10:11 PM.