Unfortunately some people may not realise that the power button on the bottom of the Start Menu does not actually turn the computer OFF.
The default setting for this button is just to put the computer into sleep mode (standby)
So unless you actually use the small arrow to the right and select "Shut Down" the computer remains in sleep mode when this button is used.
However it only takes a couple of minutes to convert the "Sleep Button" to a "OFF Button" by following the steps below.
First start by going to:-
Control Panel, then chose "Power Options"
When the Power Options window is open, on the left-hand side there are several options, one of which is called:
"Chose what the power buttons do" (to be honest I have yet to discover what it actually does, so that's not what we want, although I think it may refer to the power button on the actual computer case).
What we want are the three options on the right-hand side of the screen called:
Balanced, Power saver and High performance.
So select the first one by clicking "Change plan settings"
On this next page you can also change when the display is turned off and when the computer goes into sleep mode (standby)
Now select "Change advanced power settings"
in the next window that opens chose "Power buttons and lid"
followed by "Start menu power button" then change that from sleep to"Shut down"
You will need to do this with all of the three power options.
So now just hit the back arrow (top left-hand corner) and change the other two options.
There is also the option to "Restore default settings for this plan" on each of the three windows should you wish to do so.
You will also notice that when you now hover the mouse pointer over the power button it should now be red and the text display will tell you that it is going to turn off the computer.
(Previously it was Green and said it was going to put the computer to sleep)
Now whenever you press this Power button on the start menu, the computer will actually turn off and not go into sleep mode.