A single computer is often shared between multiple users, Windows XP, Windows Vista, Windows 7 makes it easier for users to share a computer using the Fast User Switching feature enabled, it allows more than one user to log on simultaneously at a single computer, for example, if you are currently logged onto a computer, another user can log on to watch movies, without you having to close your open programs and log off. Once the user is finished, you can return to your session where all your programs will still be running.
In Windows 7 / Vista – Method 1: Using Local Group Policy Editor
Click Start, type gpedit.msc in the Start Search or Run dialog box and press Enter.
Now navigate to the following location: