Guest Account

[NoOp]

Last month some relatives visited & used my son's system to browse the
web etc., on his Dapper system. Unfortunately they left a few
'undesirable' png files on his system. So I created a "guest" type
account that they can use for the next visit; the type with nothing
checked in the User Privileges except Use Audio Devices. That gives them
Firefox and a few other programs they can run. However, I'd like to
secure their access a little further:

1. The Windows drive (it's a dual boot machine) shows up as an icon on
the desktop & in Nautilus. How can I block the user from seeing and/or
accessing the Windows drive?

2. Nautilus allows them to see the File System directories. How can I
block this user from seeing and/or accessing File System?

In essence I'd like to have the user account only access Firefox for
browsing & checking their webmail & possibly OpenOffice. Obviously I can
remove Places from the Gnome panel & applications menus, but wondered if
there is any other simple way to just set up a vanilla desktop with
*very* limited access.