how can i restrict users to install and access a program without making another limited account in my COMPUTER?

thanks in advanceWhat's wrong with creating an account?How MANY accounts do you have in your computer?
Do you have a guest account?As far as i know the guest account is only avaliable in WINDOWS xp & vista.....for now. i only have 1 account...admin acct

but i wanna do is everytime they open or install a program, they have to enter the admin name and my password... i saw it in my old frend before, so i wanna try that.

can you teach me how?Was he on a Vista?

It is possible he configured Windows Defender to do so.Why don't you create limited account?win XP Pro

i also try to create a limited account before but whenever i try to install in that acct i cant  because of the limited use of that acct. i want to do that for everytime i want to install and open any program, i can do it ANYTIME in any acct.

I'm lost. First, you say, you don't want people to install ANYTHING, then, you complain, that you can't install, because account is limited.I think he wants something like a security clearance to install programs.

"You have chosen to install firefox.exe. Please present password"If so, maybe here: http://www.pctools.com/guides/registry/detail/1062/sorry guys if i can't explain clearly...
broni was correct, it is confusing...anyway, like carbon dudeoxide said, i want security clearance to install program. thanks for that...

anyway, here what i wanna do:

whenever they are in user acct they are not allowed to install anything in my pc just the admin can install on it. same in opening a selected program. before they install or open a program, they will prompt to enter the admin name and its password something like that.

hope this one is clear.
thanks guysCheck my link, then.