No context menu appearing can just mean you don't have permissions to do anything (even open or read) the thing you have right-clicked.
Can you open the file or folder you are right-clicking?
Does the same menu work in the same situation in Explorer? (Try using some of the menu items to check they work, not just that they appear.) Still in Explorer, does the full menu display, or just a reduced menu with basic options?
What do the debug steps in Crash, exit or high CPU when viewing certain directories output? Does disabling shell extensions ("Hide Windows items...") make a difference?