Many thanks for the replies as I can show them to my 20something know it all to convince him to get the machine checked as us old folks know nothing about computers.
One point though if I am not being computer illiterate. I have a Seagram external hard drive which I use to keep photos and documents on. He has downloaded photos from his machine and camera onto this device. Is there anyway the virus/infection could have transferred to my hard drive and then onto my machine when I plugged the hard drive in to my machine?