Game was working fine up until a few days ago, and I believe it was an install of Tera online that caused the problem. The extremely annoying thing is that D2 is my only game that does not work in Windows 7 x64 now. I have the GOG version installed, and I have done a clean re-install with the same results.
I can switch easily to WinXP (dual boot) and use the same install and hardware and D2 works perfectly so it is definitely on Windows 7 that it will crash just after the loading screen with a generic error. What is it exactly that D2 needs in Win7? Is it something with the codecs?
I checked Fallout 3 and Oblivion since they also use the Gamebryo engine, and they run just fine. I have tried everything suggested that I could find and I am convinced it is D2 alone that has a problem.
I did run your troubleshooting utility, but it passed the initial tests and checked all of the install files apparently. My install is fine, it's the engine that needs something specific in Win7.