Ok, some OEM's put stripped down BIOS into their systems. But your system is new enough to have UEFI - Boot to Windows 8 and go into PC settings, get into Advanced Boot Options and boot to UEFI - The power settings should be in there. If the power settings are there, set them and try Hibernating again. If not...
With a brand new system like this, I would copy off all of my important data, back up any Program Installers you need, and to a Full System Recovery using F11 or whatever key you need to use. There should be a recovery partition on the main drive, just look through the Sony user's manual as to what key to press to get into that.
I suggest this, because it sounds like you need to either try SFC /scannow, a DISM Image recovery, or an In-Place Install, in order to do an In-Place Install you need to have a Windows 8 Install Disk which is the exact OS that you have installed. Sometimes it is just easier to use the Recovery Partition, you don't need an install disk for that, and it will put everything back in it's place, you'll just have to re-install any Programs you had, save any relevant files. With a new system, I would just do this. But once the system gets a few years old, I would try to find some install disks for whatever OS you end up using.