Installed D2 last week and played a few days no problems. Since Sunday when i hit play it won't start. Play button just goes back to green. uninstalled and reinstalled GOG Galaxy, still not starting. Tried repairing/verifing didn't work. Uninstalled the game and downloaded it all over, still doesn't work
Thanks!

Dumb question... Have you rebooted your computer recently (You should)? And what are your specs (OS, CPU, GPU)?

Do your other games work fine?

Has your computer received any updates lately that may have broken the compatibility, like Windows 10 replacing your graphics drivers with some crappy drivers (try reinstalling your graphics drivers), or resetted some setting to a default value (like disabling DirectPlay)?

Yes, I have restarted a few times. Win 10, intel i7 X2, nvidia 940mx
Gme worked, game stopped working Win 10 Oct. update happened, game still not starting at all.
Did some of the troubleshooters on GOG site.
I only have 3 games in GOG and the other 2 work just fine.
That is as far as I've gotten
Thanks!
PS - when I do the verify/repair option, it just sits there are 0.0% complete in perpetuity

Well there's your problem.

Windows 10 updates have previously notoriously broken game compatibility.

I'd recommend you use Win7 SP1 and disabled updates. But that's my opinion.