Reboot your system.
What happens when you try? Any error messages? Like access denied or you do not have blah blah?
Right click the folder and choose properties.
Select the security tab in the resultant dialog box.
Click the advanced button
Select the Owner tab
if you are not the current owner and you name is present in the Change owner to: box select your username to give youself ownership of the folder.
If you name is not present click the edit button, the the Other users or groups button, then the Advanced Button, then the Find Now button find your name in the list of users and groups, double click it and OK your way back out of there making sure to check the box that says Replace ownere on subcontainers and objects.
Back on the security tab, double check and make sure your username has full control and OK your way back out of there.
Now you should be able to delete it.