To Roy and anyone else:

I thought I had sent the steps I took to fix the problem of dropbox
automatically importing files from my main working thumb drive, but
apparently my post didn't get through to everyone.

So, here's what I said last night:

The steps below were given to me by Joseph the Free Tech Guy. ... Thanks
Joseph:

I know you can be much more specific with all of this, in terms of
customizing preferences for particular types of media and programs, but I
have decided to keep it simple at this point.

1. Press Windows key and type the following into the Start menu search
box:
autoplay

2. You will land on the following setting:
"Use AutoPlay for all media and devices check box."
You can uncheck this checkbox, and whenever you place a CD, DVD, thumb
drive, external hard drive, etc, Windows will not show the screen which asks
you what you want to do with the media you've just placed into your
computer's drive nor will it take action on the attached media.

I hope this helps.

Dr. Tom Behler