krautkleid: I installed the update 1.04 synced my gamesaves (didnt work), which I dont think played into this. Restarted my pc. After starting gog again, savefile sync worked and the game started without a cough. Hope this helps. See you in NC.
edit: one little thing I did too, I have the Geforce Experience client.. (yeah, I know) and I tried to start the game in that client too. Nothing worked or even showed up in the taskmanager. After that I restarted. I think what happened is Nvidia overwrote some grafic settings, since when I went into the game my resolution was lower and some settings different. Maybe that fixed the starting/flatline issue I had before aswell.
Tried that thing with the GeForce Experience too, didn't help. Logo, sound starts, flatline. No matter what...