I recently tried to use the 'Move' feature within the Dropbox preferences to change the location of the 'My Dropbox' folder on my work computer. About halfway through the move operation I got an error message indicating that I would need to finish the move manually and then re-associate my computer with my Dropbox account.
After clearing the error dialog the Dropbox process hung and I was unable to kill it using Task Manager. I tried uninstalling and re-installing only to have the same hang happen again.
I'm now unable to get Dropbox installed and working on this PC. I've even tried using System Restore to roll back settings to a day prior to when this issue started to no avail.