This guide will help you to get your game back to the point in which it was before it failed to run properly.

Note that to use this guide you experienced this:
1.- You ran the game fine before. It may work for first product users, but I dont promise it.
2.- You accidentally were experimenting with the video settings while in-game and you messed the aspect ratio or your resolution.
3.- You are locked up in fullscreen, you hear audio but you only see a black screen.

If you are in this situation. Even deleting your .cfg file from your savegame folder inside your users folder will not save you.

What you need to do to fix this problem is the following.

1.- Open steam, search DOOM in your library, finally right click and select properties.
2.- Set this as launch option for DOOM: -windowed -sw -Graphics.aspectRatio "16:10" -novid
3.- Open the game, you should see video now, and you also should have a windowed mode.
4.- Fix everything in your in-game video settings, and you are all set to play.

PS: Do not mess with your aspect ratio. DOOM gave me an option to choose an aspect ratio of 128:75. I fell into it, and I screwed my game up. Dont do it again.

Everything should be working now. If you have a problem regarding anything in this guide, or something similar. Let me know. I may be able to help you with the stuff I learned fixing my DOOM.

Also credit to two users that helped me in the very first original post in which I was requesting help about this. The users are lostnumber and Ryan. Thanks again.
http://psteamcommunity.yuanyoumao.com/app/379720/discussions/0/357286119107696387/

Best Regards,
Jam