Switch users without logging off in Windows 7

For switching users without restarting your computer, use Fast User Switching. Fast User Switching feature allows other users to use your computer without logging you off or closing your files or programs. To switch users, perform the following steps:
1. Click Start button . Click the arrow button to the right of Shut down and then click Switch user.
2. Press Ctrl + Alt + Delete (If secure logon is enabled).
3. Click on the user account that you want to switch to.