Windows Explorer Weirdness

I could have written this opening paragraph:

For the past couple of months I have been coping with an incredibly frustrating problem. My files in the File Open dialog box mysteriously started appearing in order of the 'Last Modified" date, instead of in alphabetical order. Let me tell you, this problem was driving me nuts. Our Web site has more than 200 files in it and wading through the list NONalphabetically has been one gigantic pain. I figured at some point I must have clicked just the right key combination to change some Windows default setting somewhere. But I couldn't put it back. (Oh the aggravation!)

Susan has been nice enough to post her solution here (with many accolades from people like me): Windows Explorer Weirdness