Are you able to right click on desktop?Make sure a key named 'NoViewContextMenu' doesn't exist with value 1 at these locations-
Code:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\ExplorerHKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
If they do, delete them or change their value to 0, reboot and try right clicking again.