I'm not sure what you'd like to accomplish here; can you please elaborate on your query a bit?
While we're at it, are you using the desktop application or just the website to access your files?
If you were looking for a way to set up a password for your Dropbox folder (assuming that you use the desktop app), note that it's not possible to password protect Dropbox, or any of the folders inside.
We recommend that you follow good security practices to protect your entire computer. It's a good idea to require a password to log in to your account, and to resume from sleep, screen savers and lock screens.
I hope this helps to some extent and I'll be waiting for your response to have a better look into this Bob.