Support would probably be you're best bet, but you can try a few low tech things just in case.
1. Remove all mods from the game, return any nvidia or amd settings to their defaults, remove any overlay programs like ati tray tools or afterburner, reinstall directx and try to launch it again.
2. If you're able to get to workshop, then return all values to their default settings and try again. If you can't launch WOFF, then If you had a backup copy of your WOFF directory, then simply remove the old and replace with the copy.