And I was very sad.
I've had that camera for nearly 30 years now.
But, I fixed it! Luckily, and Im not quite sure how I did but I wanted to share what I think the problem is so any other Pentax ME Super users can watch out for this problem.
After changing the lenses around a bunch today, I pressed the shutter and it stuck and the film advance lever was stuck. I lost 8 shots on my roll of Ektar because not even the rewind worked. When I took the lens off, I saw this black stuff all over the inside of the camera and I could see that this rubbery, spongy material at the top of the metal ring that makes up the lens mount had pretty much disintegrated with all the lens changing.
After much futzing around with it, the curtain finally came down and the shutter and film advance started working again. I think what happened was that a bit of that rubbery stuff got stuck somewhere between the curtain the shutter and froze the curtain in the up position. By me moving the shutter around with my fingers a little bit (a very little bit because it just wouldnt move and I was afraid of bending it.), I think I dislodged the lodger and down came the curtain.
Anyway, those of you with Pentax ME Supers might want to see if that rubbery stuff is there and if its in bad shape, get rid of it before it flies everywhere in your camera and messes it up. I still have that stuff everywhere. I think a toothbrush and compressed air might get it all off and out of the camera.