Denying access to Windows Explorer

Hello,

I have successfully created a limited user account for
kids, certain relatives, etc. The limited user account
denies access to things like control panel extensions,
defrag, specified paths, etc. (Control Panel Admin Tools
Local Security Policy (settings).

What I can't figure out is how to deny access to Windows
Explorer. They can still access it through the Start Menu,
or just simply pressing Windows Key + E. Any ideas how to
deny access while in the limited user account? Any help
would be much appreciated.

Sincerely,
PlainDave