Reinstalled the Dropbox app and it wants to rename my Dropbox folder

Sure, muddleglum! A visual would definitely be appreciated. 

If possible, I’d like a screenshot of what you see right after clicking on the “Choose another location” button (as shown above) and one more of what happens next.

Nancy, Did you read the other reply I wrote at about the same time as my earlier one (that you are replying to)? I'm sure that might be a clue. II'm having a HARD time clicking the buttons on your "Welcome to Dropbox!," etc. dialogs. The buttons have to be guessed at unless they are doubled. Are you sure that this is for windows 10? I have given you'all one screenshot of "Advance Settings" that show some doubling. However, none of the other screenshots show any problem, even the worst of them.
Anyway, I'm slowing feeling my way again, as usual, hoping that I don't push the wrong button. Fun.

Hey muddleglum, I've been reading through this thread, trying to figure things out, but I need some clarifications.

What do you mean by "doubling"?

Also, you mentioned the following: "I tried "Choose another folder" got another dialog box that allowed me to type in a new name, hit enter, then another dialog box came up saying that it cannot make a new folder."

Can you let me know what you typed in as a name and send me a screenshot of the next dialog box that said you cannot make a new folder?

Doubling? The below has already been sent. Notice the right side is doubled -- the table is pretty clearly doubled. However, this is the only screenshot that I could capture even a portion of the doubling. Note that the left hand table is the one added to this dialog box. Note also that it is smaller (see the difference of the cup handles?) and set higher. Remember that height (HT) -- it is the difference between the real and fake buttons (that you cannot see).

Do you see on the left the checkbox with the text, "Save files as online only"? To click that, I had to scout around beneath the "Done" button below that, to find the blank area where I could uncheck the checkbox. I now know that it was HT below it and, I think, a bit to the side. The "Done" button, itself, was doubled and about the same height HT away and smaller as the cup handle is smaller.

Confused? I certainly was. See beneath this screenshot for more discussion.

I'm fairly sure now that on a previous dialog that I clicked the wrong thing. No, I clicked the right thing, but not the right place on the dialog box where the real button lay hidden. So, after I found I couldn't get out of that dialog box by clicking obvious buttons, I hit return. I ended up getting a new account and your program tried to use my real account. I don't know how to get out of this now, and back to my old account. (Note that all this is happening on another computer that is still hooked up with my old account.)

Hey muddleglum, here's what I'd suggest.

I suggest that you perform an advanced reinstall using these steps. 

When you reach step 11, which is the re-installation part make sure to remove any old Dropbox folder copies from your directories.

If you have any content that you think hasn't been synced to your account online, make sure to keep a separate copy on your hard drive. 

Then, reinstall the app and allow for the content to sync from scratch. This might do the trick.