Disabling right click on all programs

[Kelly]

Hi There
I have a very tight gpo on my users and have hidden the
c drive as well as disabling the ability to browse the
network. There seems to be one way round this though. If
you go to start, all programs and right click it, you are
given the option to explore and can see everything!
Anyone know how to disable this?
Ta muchly in advance
Kelly