Special Logon starting PC in middle of night

[LibraOnAmission]

Hope I'm not being dumb here and sure I powered my PC off before bed, but at 3.55 am this morning the wife and I were awoken by a loud conversation from the office where my PC is held! I went in to discover the PC powered up and something active on it.. I wanted to check what but getting lots of verbal from the missis I powered it down. Checking this morning on the event viewer I found activity on the PC from User account management and "Special Logon"..
Question; is this Microsoft logging on to do upgrades or is it feasible that the system is being logged onto by someone else? Attached is a screenshot of the event viewer capture.. any guidance gratefully received.. Thanks

 

[Trouble]

DWM-# is the Desktop Windows Manager process.
I suspect it is likely, one of the many behind the scenes services doing its' thing while the machine is idle.

 

[LibraOnAmission]

DWM-# is the Desktop Windows Manager process.
I suspect it is likely, one of the many behind the scenes services doing its' thing while the machine is idle.

Appreciated.. that's put my mind at rest.. thanks for responding..