using Admin credentials on a standard user

I am fairly new to most admin techniques but i know you can run an application (like cmd.exe) as an administrator, while the standard user is still signed into their account. Im just not sure how you do this, i have tried right clicking and running as an admin but it never prompts me to enter the Admin credentials...

So to clarify with an example, if i have a user as standard user, and i want to quickly be able to delete a file from the windows/system32 folder by keeping the current standard user still signed in how do i do this. I was under the impression that if i try to use "run as administrator" it would then prompt me to put in my Admin credentials but it does not.

windows 7 64bit, on a workgroup domain.... some of the employees i have had edited some windows files they shouldn't have, so in order to prevent them from continuing to do so i made them all standard users, but now i dont know how to use my admin account without having them sign out and then having to sign in with the admin account.

thanks, that is what i thought but i wasn't sure if UAC was the issue since it just wasn't prompting me to enter the password when i clicked run as admin, i will double check that tho, much appreciated

okay so UAC is active but its not prompting me to put in a password, maybe the UAC settings are not set how i think they are supposed to be