@johnlockefromlost wrote:
When I unselect "PC" or all the subfolders under "PC" in my preferences and hit apply, it does nothing. If I open up the selective sync preferences again, those folders are re-checked.
You can't use Selective Sync to remove that folder. The "backup" feature works by MOVING your Desktop, Documents and Downloads folders into the Dropbox folder. If Select Sync allowed you to remove the PC folder, you'd be removing your actual Desktop and other folders from the computer.
As long as you unlink your computer from your Dropbox account, you can factory reset it without it deleting the files in your account online. Just make sure your sync is finished and Dropbox is showing Up-to-date before you unlink the computer.