I didn't see this mentioned anywhere else on the forum, so I figured I'd ask.

When I go into Duke3D's setup program, change the resolution to 640x480 or 800x600, save the changes, and try to run the game, it crashes back to the desktop before the intro clip of the radioactive symbol.

I'm on Windows 7 64-bit, and I've tried running gogwrap.exe as an administrator and have tried the DDraw and OpenGL graphics modes.

Also, I know about eDuke, but I would like to play it in a "pure" DOS environment if I can. Thanks!

You do know that eDuke will play the game in a "pure" way? You can have all the modern lighting and graphics turned off and play it just as it plays in DOS. Though eDuke has a vastly better mouselook than the DOS game does.

As for the issue you are having, I've no idea, not heard of that one before. I used to have a similar issue when I played the DOS version from Windows 98, way back when I first played Duke Nukem. Whenever I descended into the sewer in the first level it would crash to Windows. That issue was a sound emulation issue that 3D Realms released a patch for, though. You could always try that patch. It's still on the 3D Realms site.

http://www.3drealms.com/downloads.html

In the Duke Nukem 3D section look for the dnsndfx.exe patch.

Ah, yes, the executable running with administrator rights. Always a good thing to try.

Also, did you install into Program Files, by any chance? I recommend not doing that either, as with the release of Vista and UAC/DEP, Program Files has become protected (to prevent unauthorised alteration of files in there) and this can cause issues with older games which try to store their settings in the install folder.