Forced to have multiple Admins. Privacy?

Hey everyone, first post here on these forums.

So, my understanding is that Windows 7 still does not include some whitelist feature to allow standard users to install programs.
i.e. My young sisters cannot install their games, and therefore I'm just going to make them admin accounts so they don't have to call my cell to install PetVet.

Is there a way I can protect my files on my admin account from their admin accounts?

Something is currently wrong in the sharing anyways as they can access my user files from standard accounts anyways. What can I do?

Thanks so much.

That User folder access problem is usually only encountered when attempting to use the Homegroup networking feature in a mixed Op system network. If you are using mixed Op systems you need to set up a workgroup type network instead.:)