Windows 8 unhibernates every day at 4AM

[Lexic]

I hibernate my computer every night before going to sleep because it is a noisy bastard.
This was fine when I was using Windows 7, but now I've switched to Windows 8 it has started unhibernating itself every single night at 4AM.
No matter what I do (short of literally unplugging it), it will start up and generally start making other noises.
I've got maintenence mode off:
[img]http://i.imgur.com/bsYuV.png[/img]
I'm sure it has something to do with Windows Defender's nightly definitions update since that is the first thing that greets me each time, but windows update has no relevant settings and neither does anything else.
Halp?

[editline]9th October 2012[/editline]

[img]http://i.imgur.com/onjOj.png[/img]