If you are working on sensitive material and need to leave your computer unattended for a while, you can lock it so that no one can use it without your permission. While your computer is locked, all your programs continue to run. When you return to your computer, you can access your computer in the same way you started Windows. If you have Fast User Switching turned on, the Welcome screen appears. If it is turned off or you work on a network domain, the Locked Computer dialog box appears.
Lock and Unlock the Computer