So, every time I hit a checkpoint, the game crashes. I have no problems loading checkpoints, but any time I hit a new one, the game immediately crashes and, while it seems to save my nano points and acquired weapon attachments, fails to save my level progress.

After having these problems, I installed the game on my wife's computer and discovered it runs perfectly. I can move those saves back to my computer and crash every time I hit the next checkpoint further on.

Our computers have somewhat similar hardware. After doing some extensive searching, I've noticed everyone with similar issues seems to have Vista/7 x64 and an nVidia graphics card. My own situation supports this. I have tried everything I can think of from reinstalling the game to running in compatibility modes. Needless to say the game, OS, graphics driver, and sound driver are updated. Hardware is as follows:

OS: Windows 7 Ultimate x64
Graphics: nVidia GeForce 250 GTS
Sound: Sound Blaster X-Fi
Processor: AMD Phenom x4
RAM: 4GB DDR2-1066

OS: Windows 7 Pro x86
Graphics: nVidia GeForce 250 GTS
Sound: Integrated
Processor: AMD Phenom x4
RAM: 3GB DDR2-667

The latter box has absolutely no problems. While I don't mind playing it on the 55" TV her media center is hooked up to, the bluetooth keyboard really isn't conducive to gaming (it has issues with modifier keys pressed while letter keys are held), plus I miss my Klipsch surround speakers I have at my desk. I may try installing Win7 x86 in a temporary VHD and see if it works on mine, but I really have a feeling that'll do it. Although that's an awful workaround to run a buggy game. Has anyone been able to find a real solution to this?

Maybe it's the sound card?

I didn't think that was it, but I tried disabling all playback devices and playing the game again. Still crashed at the next checkpoint.