Thank you for your quick replies. We made some progress 
I can play my work again, and midi keyboard entry will sound notes. Dorico no longer crashes in the first few seconds. But it still takes exclusive control of the audio driver. Anything that needs the sound will just hang, including Media Player, YouTube, Pandora and Cakewalk. I have to reboot to get access.
To get to this point, I went into Edit | Device Setup. I found Dorico detected the Audiobox USB ASIO. That does not have an exclusive control option in its control. Just for grins, I changed the driver to the Generic one and turned off the exclusive use there. After a save and reboot, there was no change. I changed the driver back to Audiobox, rebooted, and Dorico started to work. But I need to have everything with access at the same time like it was at first.
Traubitz, there was a driver update. I applied it after my last step above. If I have need to change sample rate I will follow your advice.
(For future reference, I did find an exclusive use checkbox for the Audiobox in the Windows Sound settings. In Playback Devices, a click of the Properties button will bring up another dialog window with the “exclusive use” checkbox. It was checked. I don’t know if that is a change from before. But when I turned it off, Dorico would not play.)