Bugger, it got me, it came disguised as a request for a student file. Thanks to the good advice on here, I think I've got rid of it by downloading that file thingy. First time around it said I had been unsuccessful in getting rid of the virus, second time around it worked (or said it did)
I dread to think how many of my confidential files have been disseminated. I only realised when one of them bounced back.
So thank you again to all of you clever computer people here on Pprune for showing the way to get rid of it and I promise I won't open strange attachments again!