If you use Dropbox and the Libraries feature in Windows 7, you can use them in parallel. Here’s how to add Dropbox to Windows 7 Libraries.
Click Start then Documents to open Windows Explorer.
In the right panel you’ll find the list of Libraries.
Click on Libraries to open the default Libraries in Windows 7.
Next, click on New Library.
Name the new Library Dropbox.
Now right-click on the Library you just created and select Properties.
In the Dropbox Properties window click Include a Folder.
Browse to your Dropbox folder. Highlight it and click Include Folder.
The My Dropbox folder will be listed in the Library Locations field. Click OK.
That’s it. Now you have easy access to your Dropbox folder when you have Windows Explorer open.