Disable Context Menus for 'All Programs' on Start Menu

Although I have sucessfully disables the right click function to limit access
to the 'task bar', 'start' button, and desktop using GPO's I cant find
anything that stops my users right clicking on 'All Programs' and pulling up
a context menu that allows them instant access to Explorer using the
'explore' option.



What is the standard method of limiting access to this function?



I run a win2000 server based Active Directory network with all machines
running WinXP Prof.



Many Thanks,



Dave Lomax