Fran, I have been plagued by this junk for about five days now too, but only on some of the threads.
I searched my own compootah for signs that it could have been picked up elsewhere but it seems to be here only.
All my "antispam, antiworm, antitrojan and antitroll" ware says it isn't in my machine so I reluctantly think it is off someone else's machine...
The only way I can stop it is to hit the CROSS in the corner!

bill