Have you updated to the newest patch? - if not, I suggest manually deleting the one you have then downloading the new one. Repairing your game might also help.
I also know that mods don't play nice on launch day, so don't use a modded patch.
I have the same problem but mods doesn't seem to be the thing.
-I got path 10
-I was to start The Descent DLC and removed ALL mods (because I'd heard there were problems with that)
-I re-merged my patch with the mods after getting The Descent opening cutscene out of the way but by then Trespasser was finally available in Europe so I installed that
-Now the game won't start (just synching data then nothing)
-Neither can I remove any mods or add new ones as the Tools Suite says the file cas_01.cas is in use elsewhere (no note on where exactly though)
-I've tried compatibility mode and repairing the game
I run Win 8.1, 64bit, 3.30 GHz processor, 8GB RAM.
Funny that the game ran just fine earlier today. The only thing that changed was after installing Trespasser. I think Solas is blocking me from getting those answers...
@Teshyra: I figured that trying to use mods on launch day would be a bad idea, so I removed all mods too, and ran into the same problem you did anyway. Have you tried deleting the mod manager patch? That worked for me.
