You don't say how or where you are editing Group Policy; are you using a
domain controller or are you editing the local machine's policies?
You are not looking to disable the minimize/maximise/close buttons, these
are system default and as far as I know can not be removed.
Like I said in my first reply, you would rather be looking to lock down
the desktop and system components from unauthorised access using either
Windows SteadyState, or alternatively if the machines are members of a
domain, through Active Directory's Group Policy objects.
You said you do not want people to exit your program.
You can make it pointless to exit your program by stripping the users
from all other rights, except to run your program.
For a single computer, use Windows SteadyState and set up your accounts,
you will find all you need in Windows SteadyState to lock down a user's
account.
http://download.microsoft.com
For multiple networked computers, use Active Directory Group Policy
Objects and set up users grouped by Organisational Unit with a Group
Policy linked to that Organisational Unit.
This is available to you when your computer is connected to a Windows
Server domain controller.
Explaining the full capability of Active Directory Group Policies goes
far beyond my capabilities and time; there are simply too many options.
Alternatively if you insist on using Group Policy Objects on a single
computer, you can click Start, Run, type 'gpedit.msc' and click OK.
You will get the local Group Policy Editor for that single machine on
your screen.
You are limited to the 'User' section, note however that the settings
made here will apply to ALL USERS on that machine, including your admin
account - and you do not want that.
Also the options for the local machine are more limited than those found
in Active Directory.
You will not be able to remove the standard minimize/maximise/close
buttons.
