Original objective seemed trivial. Wanted to download a copy of my old files from the Dropbox cloud down to a different computer. After several attempts and a lot of time, I was unable to do that from the browser. (That included posting here. No useful answer but much lower expectations now.) So I finally gave up on that approach and downloaded the standalone version. That worked as I remembered it, allowing me to copy the files out of the Dropbox directory.
Having accomplished my objective, I decided to uninstall Dropbox. No error messages during installation or uninstallation. However, after it was uninstalled I discovered that my computer was extremely seriously messed up. Now the Documents folder has been moved down into a subdirectory of Dropbox. The new directory structure looks like this:
file:///C:/Users/<my user name>/Dropbox/My%20PC%20(<my computer id>)/Documents/TargetDays.html
That "Dropbox" in the middle is screwing everything up. Massively. Apparently this was created in the installation process and left behind after it was uninstalled. I want to use much stronger language, but what I can definitely say is that I will NEVER trust Dropbox again. I have a couple of theories about what went wrong, but I don't care much about figuring out such incompetence.