Still doesn't even start the process, with the dev option selected.

How do I download the dev build from steam?

I'm not changing my hardware, that's just silly. I'll try removing my firewall completely and re-installing. I'm not using any mods.

No GUI shows up, steam launch options are blank and no process is running.

I have closed Steam and started it again, I've also checked the game cache. It came back fine. Game still doesn't start.

Note: I have ZoneAlarm but I disabled it when trying to start the game.