Bob, I sympathize. I think this is a Windows 10 thing. After the latest upgrade I cannot change several default applications. Believe me it's not through lack of trying. I've tried every method available.
Can you change it from here, or is this where it doesn't show:

Attached Files (Click to download or enlarge) (Only available when you are logged in)
2018-10-28_04-28-16.jpg (39.8 KB, 72 downloads)
2018-10-28_04-27-27.jpg (61.92 KB, 72 downloads)

BIAB & RB2025 Win.(Audiophile), Sonar Platinum, Cakewalk by Bandlab, Izotope Prod.Bundle, Roland RD-1000, Synthogy Ivory, Kontakt, Focusrite 18i20, KetronSD2, NS40M Monitors, Pioneer Active Monitors, AKG K271 Studio H'phones