Hello Wildpig1234 Welcome to the Se7en Forums!
When seeing two different amounts of drive space used one thing to add into the mix there is the paging file seen with any Windows installation by default. Windows reserves a certain amount of drive space for that as well as the creation of new system restore points.
As for options at shutdown, logooff, restart you bring over the dropdown menu to the right for seleting one or the other. For changing the default option seen for the button itsself you Birng up the Start menu and right click on a blank spot to select "properties" and go to the "power button options" to select one from the dropdown list of choices in the properties screen there.
The images here will show how those look.