Having a similar problem where DA:I won't launch. It launched last night with ease. No complications or problems. I then decided to exit the game to check up some things - instead of tabbing out - and then went back to reload the game up. Nothing was installed or changed about my PC between the two loads up, except DA:I now no longer loads up.
The last successful load up was from Origins, and I've tried loading it up from Origins and all that happens is that it appears briefly under my Origins status before disappearing again, but nothing is actually loading up. No black windows, and it's not under my Processes either.
I've tried repairing, running as an administrator for both the game and origins, disabling my mods, disabling Origins in the game, turning off my firewall - I don't use Avast so it's not that - and turning off Razer Synapse as I saw one post that said that helped. None of these solutions have worked.
I'm not entirely sure what's happened between these two instances to cause the game not to load up. Nothing has changed on my PC, nor my set up. Everything is exactly the same.
My DxDiag is here: https://hastebin.com/ufovamaceg.tex