to modify the windows right click menu
FOR SPECIFIC FILE TYPES
Tools -> Folder Options File Types
TO REMOVE A WHOLE APPLICATION CHOICE regedit (make sure you back up before you make any changes!)
HKEY_CLASSES_ROOT*\shellexe\ContextMenuHandlers
delete the "folder" for each application (e.g. winrar or winzip) that you no longer want to see as a "context menu"
TO ADD ITEMS
http://www.jfitz.com/tips/rclick_custom.html