Did you try to use the in game resolution aka ini, sometimes the default resolution sticks and does not upscale.
Ingame resolution? I am unable to access res in game actually. Would a mod be interfering with that? It's been so long since I've used vanilla I can't even remember. Maybe skyui or something?
That aside though, the "bFull Screen=1" tag should still stretch it across the monitor even if it was at a smaller resolution just as you can run other games on full screen at lower resolutions than native.
I believe he's referring to one of the skyrim.ini settings. Afaik there's one that defines your game res. (HxV)
I'm not seeing it in there to change. I assume I am safe to add it to the display header group correct?