Well, after days of scouring the wisdom of the internet top to bottom, I have finally caved and decided to post my own cry for help. So up until recently, I've always played Fallout 3 on my PS3/Xbox, but I decided to finally try it on the PC, ignoring the tiny voice in my head to do so otherwise. So, I play the game for about 2-3 hours, and everything is running smoothly. My rig isn't built to run games, really, however it's strong enough to run Fallout on medium to high settings with minimum stutter. I get out of the vault, head to Megaton, and spend some time running around. Then I get a crash after entering Springvale Elementary School. I though to myself "Huh...weird..." but I ignored it and rebooted the game. Same thing happened. After several hours of tinkering with the game settings and my mods, I established that my game only crashes when I try to perform a save of any kind, be it autosave or a regular save. So, I disabled autosave, uninstalled CASM (which I had previously installed because of this problem) and went looking for fixes. However, I have never found a permanent fix. Sometimes, the game would start working again for seemingly no reason, only to begin crashing repeatedly again the next day. And now, it seems that the crashes are here to stay. I was having such an enjoyable time playing this game, as it is one of my favorites, but this problem is really beginning to kill it for me.

Here's a list of everything I've already tried, just so we don't waste any time here:

Uninstalling/re-installing Fallout 3 AND all my mods

Installing my Fallout 3 directory in C:/Games intead of Programs x 86 folder.

Editing INI file (both in My Games and in Fallout 3 directory)

Installed d3d9.dll into Fallout 3 directory

Created a merge patch for all my mods using FO3Edit

Running Fallout (FOSE) in Windows XP (Service Pack 2) compatibility mode

Installed Fallout 3 4GB Enabler mod

Unistalled some of my much larger mods to free up some space

Loading previous saves before loading my actual save (recommended by internet)

Loading my save file twice (recommended by internet)

Killing/Blowing myself up after loading my game (this one seemed to be doing the trick at first, but now looks like it's stopped working altogether)

Well sorry you are having issues with your game?

why did you install d3d9.dll. If you using that to bypass an Intel videocard check at launch than that could still be a reason why you are having issues. A good portion of Intel cards are not capable of shaders or at least only a partial shaders support. If you were using an enb than that could be part of the issue as well depending on how good your computer is.

What can help us out is for you do run a dxdiag.exe and post in spoilers the results.

[edit]

I just want to make it clear that using the d3d9.dll to bypass the the video card check to run the game with an Intel Card can also cause issues for your hardware.