Sorry, my mistake.... but a WOL Client could easily be what is preventing Hibernation. Of the list Steam has a TSR as does Chrome and depending on Configuration Office has 2 to 3....OneDrive for Business, Office Upload and Lync 2013.That's right, I didn't think of it, that the SP3 uses a modified Windows and Standby.
I read what TSR's are, but how I see what program is one?
Lights-Out is a program for windows Servers to wake them with WOL and keep the computer running during backups it's not a messaging program, if you meant that with messaging program, else I don't know what you mean with that. I don't have any messengers on my Surface. Only Windows live mail, Steam, Chrome, Office and a few games.