I was re-installing dropbox on my computer and I accidently clicked to backup the desktop, downloads, and documents folders. I stopped syncing them and selected to leave the files on my PC and not on Dropbox but I still have "My PC" in my dropbox account and now have an "X" next to all the files in those 3 folders. I can't seem to delete the "MY PC" entry from my dropbox online account. How can I remove it?