Oops! It wasn't me honest guv!! I run ESET Internet Security on my puters and it has never brought anything up...and I was running Kaspersky on this machine and it never said anything.
I will get rid of it now to see if it solves the problem.
Well, after investigating my avatar, I found it was named xavatar_756.gif.wyq9989_.jpg, which I believe is the reason that some antivirus programs got upset with seeing two extensions on the one file. So not a real trogen. I downloaded the avatar from another forum (can't remember which one) ages ago, and with windows's habit of shortening names I thought its name was xavatar_756.gif.
So anyway, I have scanned the pic for viruses etc and renamed it to just xavatar.jpg and have set it back as my avatar, so hopefully it won't bring up any alerts. If it does, obviously just let me know and I will sort it out.
My deepest apologies to all, particularly Good and Bad CO, for any inconvenience caused, I shall now take myself outside and giv myself a good thrashing.