Well I gave up and simply reformatted my SSD and reinstalled Windows. From the screenshots below (Drive Properties and WinDirStat), the numbers all appear to be correct and I no longer have a problem with missing/hidden 34GB of drive space.
I became most alarmed when I read a post on this board from a person who reported a similar problem. Someone suggested their problem could be related to a virus that copied all/some files to a hidden spot/status. Personally I think one of my Blue Screens during the past week might have corrupted my SSD, but I will probably never know.
Thank you to everyone for taking the time to try to solve my problem. At least I picked up some good tips to adjust performance and eliminate wasted disk space, so the entire process was not wasted time.