After about 45-60 minutes of gameplay, screen goes black, game continues, and I still have my HUD. I have tried SEVERAL settings changes, reduced AA and AF to 0, forced a lower framerate, as the game tried to go to about 190-225 on average, I capped it at 120, still the same thing. I suppose I can blindly keep pressing buttons in DX10 video settings but I was hoping for something a bit more direct.
Attached is a pic of what I see. The longest I have had the game last was 3 maps. To be fair that was a while as I was headhunting in the enemy base, so there was ALOT going on.
Any advice would be GREATLY appreciated!

Perhaps try the OpenGL renderer?
http://www.cwdohnal.com/utglr/
Download utglr37.zip as it is the latest version.

Hmm. I'm wondering if something else is going on here. I'd have thought that if it were a renderer issue then you'd lose the HUD too, and you've now had the issue with the standard renderer and the DirectX 10 one. You can try the included OpenGL one or this new one that Soilbreeder has linked to, but I'm now not convinced that this will solve the problem.

Have you tried software mode to see if the game can manage itself? Yes, it will look ugly, but treat it as a test as it may help diagnose whether it is linked to the GPU and renderer.

The DX10 one automatically restricts the game to single core affinity so that shouldn't be the problem.

Is there anything else running in the background? Any DXDiag that you can provide when the issue happens? Have you spoken with GOG support?

The only other things I can think of at present are to kill off any other background tasks and possibly try a re-install, using Run as Administrator on the installer and when running the game (unless you've disabled UAC and such).

I **MAY** have found the issue.
I will do some more tests on it. When I have classic lighting disabled:HDR on, it seems to be crashing. When classic lighting is enabled, I get crashes.

I will do some more tests on it tomorrow, and also experiment with other settings to see if I can consistently reproduce the issue.

I will follow up more tomorrow and likely Friday/weekend.

Classic lighting in the DX10 renderer just prevents the renderer from doing it's own lighting effects, leaving the game lighting as it was originally, so I'd have thought that with classic lighting on and HDR off that you shouldn't have any issues.

But do let us know how you get on.