This is the first answer, I should have used, but I didnt test right. This is much harder on the eyes, and more dangerous.
autoruns http://technet.microsoft.com/en-us/sysinternals/bb963902
This program made by the great System Internals, is one of the most comprehensive views of all the ways and things that run on your system. You can heal or destroy a system with it, by selection, disable , enable, and delete of items. I reccomend a full image backup of your system, and a save of your settings in autoruns prior to messing with things in it.
It defaults to not showing "microsoft" entries. Which is a good way to see mostly 3rd party stuff and system additions. The items that can be more safely disabled.
To get the whole view, your going to want go to |Options| and show microsoft and windows entries. now (hold onto your eyes) go to |File| and hit |Refresh| (or F5) .
Now look in the |explorer| tab, and you will see Context Menu Handlers , and Property sheets and everything. this should allow you to disable/delete and remove the menu items completely, jump to the item in the registry, and jump to the item at its file location.
Disclaimer : Have a full image backup of your system , that does not require the system to recover (like boots from a cd or usb stick). and be very carefull. You are now in control :-)