Windows is only updating because the Automatic update time and day that is set up was probably when the computer was off. What happens is when you are on the computer one day and the set time/date to update comes around, BOOM you have 120 updates. When you restart and get more updates it is because the update can only be installed after the previous update, Microsoft is "patching their patches"
so to speak.
I leave my computer on 24/7 and have updates and McAfee definition updates set to start at 3 am, doesn't bother me a bit.