Worked 2 hours last night with no shutdowns! First time in months!
I went back to my original setup. In a different post, I explained that I was having issues with cut/copy/paste. Rharv suggested to do edit/track/consolidate audio track. I did that each time after a couple of edits. Somehow, that seems to have corrected the issue. Time will tell.
I do a lot of editing, which is when I was having my shutdown issues. Hope it is solved!
Bernie