I don't know if anyone else is having problems with this, but the fix that seems to have worked for me with my particular Win 7 configuration is to add the "-window" argument to the .exe. What this means is opening up the Nox directory, going directly to the "Game.exe" file, opening it's properties and literally typing " -window" (yes, with a SPACE before the rest of the text) behind the word "Game" in top bar. (This, apparently, is how you add command line arguments in Win7...? Who knew? Not me, anyway...) You will have to provide administrator access to finalize the change, but once you've done that... well, it worked for me, anyway. (Oh, I think I had to set the compatibility in this file manually to "Win 98/ ME." Not sure why it wasn't preset to that, but it wasn't.)
Two points:
Firstly: wow! Isn't it crazy what a slick looking game Nox is even now, over a decade later? Even in 640x480, the colors in this game just pop, and in 1024x768... forget about it! I'll be honest: Nox looks slicker to me at this stage in the game than Diablo II did when I installed it a few months back. It's amazing how some games have graphics that just *hold up* for whatever reason. Maybe that's the mark of great art direction? A couple other GOG games like this are "Outcast" (MAN, I wish someone would patch that game to run in higher resolutions!!) and both of the Twinsen games, especially the sequel. I always thought the Twinsen games were overlooked gems of 90s gaming, and that Twinsen should have become for PC games what Mario is for Nintendo. For that matter, Frederick Raynal (the creator of both the Twinsen and the Alone in the Dark series), should be a gaming celebrity on par with Cliffy B. But what do I know?
Secondly, I want to say that if Morbeous's claim is true and he couldn't get support from GOG on this issue, that is some weak sauce. I've been a huge GOG fan for a couple years now, and I definitely want to seem them succeed. That said, I'd rather seem them putting their time and effort into securing and supporting actual good old games than competing with Steam's new releases (Legend of Grimrock, Alan Wake, etc.) I love GOG, but if they think they are gonna compete with Steam, they are flat-out high on magic mushrooms and paint thinner. Steam offers insanely deep discounts on contemporary games and vastly superior online interaction.
Anyway, enough ranting. Just wanted to post my experience. I hope this helps someone else get this cool old game working.