Fallout 3 & NV crash after initial loading screen

I got New Vegas on Steam the other day, and started up a new game. Got through the intro scene, and then it was loading, and then... crashed. Out of nowhere. Every time. Have tried many things to fix it (see link), all have failed. Tried contacting Bethesda, and they replied a couple of times with non-working solutions, then stopped. Yesterday, I got Fallout 3 in another Steam sale and that has fallen to the same fate. And so, I come to Reddit, seeking whatever wisdom or guidance may or may not be hidden within these walls.