Okay... I'm not sure what happened. I was using the ENB merely for the boost. Following Kelmych's Fallout 3 - "Clear and Present Danger Guide" and its recommendation on how to set up ENBBoost. It was working well for several days.
I went to start the game yesterday and it failed to load. I went through the mods one at a time to figure out where things had gone wrong and there wasn't any conflicts. I attempted to load the game with only the ENB still active, no mods, and still failed to load. I removed ENB and it loaded.
I've gone through the settings and all are the same. It wasn't until I put reduceSystemMemoryUsage to false that the game would start up again with ENB. Problem is if I'm using ENB merely for the Boost turning off reduceSystemMemoryUsage means I don't get it. The only way that I can use ReduceSystemMemoryUsage is if I put EnableUnsafeMemoryHacks to true as well. I've read that this isn't recommended though.
Has anyone had a similar issue?
Any thoughts on how to fix?