Reboot into Safe Mode too, delete it and I assume along with the app are other elements you may have to search for, such as any plug-in it installed or use?
If so, they should have created an uninstall/installer.
Uninstalling Dropbox will not delete your Dropbox account or remove the files in your Dropbox folder from your hard drive.
https://www.dropbox.com/help/41
- Quit Dropbox (click on the Dropbox icon from the menu bar, click on the gear icon, and then select "Quit Dropbox").
- Drag-and-drop Dropbox to the trash from your Applications folder.
- Your Dropbox folder and its contents will remain intact. However, if you'd like to remove that as well, you can drag and drop your Dropbox folder to the trash.
- Open the Finder and select Go to folder... from the Go menu (or press Shift-Command-G).
- A dialog box should appear. Now copy and paste the following line into the box and press the return key:
/Library
- Delete the DropboxHelperTools folder by moving it to the Trash.
- Open the Finder and select Go to folder... from the Go menu (or press Shift-Command-G).
- A dialog box should appear. Now copy and paste the following line into the box and press the return key:
~/.dropbox
- Remove your Dropbox application system settings by selecting all files in the folder and dragging and dropping them into the trash.
http://www.bing.com/search?q=uninstall+dropbox+mac