Windows Messenger CONTINUALLY pops up "Display Name"
 

I don't use WM. I never have. I never will. I don't even want to enter a name
to display to anyone. I've lived 70 years without using it, and would be more
than content to never use it.
I suppose I could enter a user name just to shut it up, but then someone
might see that I was on-line in WM and try to communicate with me. I don't
want that.
How do I turn this thing off.....permanently? Currently, it pops up about
every 5 minutes if my computer is idle; if I click cancel, and let it be idle
again, it'll pop up again.