The only difference between this newly built PC and my old Windows 7 PC in terms of programs are now I have Norton Antivirus. I usually always leave Battle.net and Steam open, as well as AFK in my friend's Mumble server. I believe the culprit to be Norton Live Update as when I manually run a Live Update the display will sleep. But if a new update(s) have come that have not automatically downloaded (I.E, I could run it and it would update), then this seems to hang the display from ever turning off after my 15 min specified time. I have the PC to NEVER sleep.