Yet here you are effectively continuing saying you can't fullscreen these without skewing and horrible stretching because... I dunno.Yeah if me saying "Aspect Ratio is not the problem" didn't give it away, I fail to see how you continued talking about aspect ratio...
I'm not going to clutter the forum with more pointless discussion, simply not fullscreening works.
Yes. You. Can.
I guess you could be having a 16k (hmm) monitor or something, in which case I *could* imagine something getting lost during fullscreening, but otherwise if you fullscreen these 640x480 (I'm assuming) games while having those options set to preserving aspect ratio - absofuckinglutely no skewing or stretching or basically ANY noticeable quality loss should be occurring. If it does for you, something is not working/configured correctly.
Just saying.
(PS: I'm not trying to troll. You yourself said there is stretching and skewing when you try to fullscreen these. Which should not happen.)