Are you using App from the windows store, the web page, or the program you can download from drop box web site? It makes a huge difference. The only one that works even remotely different would be the App from the MS store which was not available in Windows 7. The webpage and the drop box software work the same as they did in 7.
You might want to go here
https://www.dropbox.com/downloading?src=index
download and install the software. It will then give you a folder in Windows Explorer that you can just easily copy and past to.
If you need more info let me know.