Windows 10 64bit - ADE 4.5.8 will not run

I *used* to have a ADE library. ADE is now empty and trying to open a "new library" crashes.

I *used* to be able to download .ACSM files and have the book downloaded into ADE.

I now open an ACSM file and ADE freezes with a blank screen and crashes if I try to open anything.

I have tried uninstalling, downloading (again) and reinstalling. Nothing.

I have tried deauthorizing and reauthorizing. Nothing.

I have tried deauthorize, uninstall, registry clean, reboot, reinstall, reauthorize. That at least got me up to downloading the book when I tried to open an ACSM - then nothing. No library, no way to create a library, no books, nothing. Same as before. Trying to do anything either simply freezes on the blank screen or crashes with no error message. I checked my Digital downloads - my old books are there. The new book showed up there - but I cannot open it (or any other) with any other ePub reader because of DRM lock.

HELP!!!!!!!