Thanks for the quick reply!
Did the crashes with D:OS and Way of The Samurai 4 start at the same time? Or did you only install the other game after you started having a problem with D:OS?
The order of events went as follows:
1) Installed D:OS several months ago. Had issues initially launching the game, however I was able to resolve them, though I don't remember the exact solution nor the exact symptoms. Played the game and enjoyed it for quite some time, eventually put it down, though never uninstalled it.
2)Some months later, bought WOTS4 and encountered the problem outlined above. Never was able to resolve the issue.
3) About a week later, updated D:OS (due to my ISP's rather draconian data limits, I don't generally update games unless I intend to play them soon) and tried to launch it, encountering the problem outlined above.
I'm not sure if any of that was helpful to you, but I hope so.
At any rate, I'll try everything you outlined and update with news. Thanks again for helping me troubleshoot this.
Edit/Update
Try deleting (or moving/renaming) the d3dcompiler_43.dll file in both the 'C:\Windows\system32' and 'C:\Windows\SysWOW64' folders, then reinstall DirectX 9c and reboot.
This did the trick for me, AND got WOTS4 working. You're an ace raze. You should charge them for outsourcing their problem to you.
I especially appreciated that you didn't simply respond to my bug report with a question (like *cough* some other guys), but gave me a set of possible things to try. Thanks again!