If you think that the current setting for the Start Menu power button do not match your needs, you can easily change it going through the following instructions. Many people face a lot of problem when the OS will force change the action temporarily in certain circumstances. This frequently occurs when updates require to be installed. Once the forced action occurs, the button will default to the set behavior.
Here are some necessary steps to be performed in such condition:
1. Right-click the Taskbar.
2. Select Properties.
3. Click the Start Menu tab.
4. Use the Power button action dropdown to select the desired setting such
as: Switch User, Log off, Lock, Restart, Sleep, Hibernate, or Shut Down.
5. Click OK.