Sorry to necro this, but I have some info that might be related and which might be of benefit to others who might stumble upon this post in the future so I thought that was more valuable to post.
tinyE: I think I got it running, it just takes a long time.
After I click on the icon I need to wait 2 or 3 minutes. At that point it looks and runs great; don't think I'll even be looking into any widescreen mods. She looks fantastic.
Interesting... I never tried waiting longer myself. If that works there are two problems that can have that symptom that I know of, but it could be something else also.
1) SMP cache thrashing. Multi-threaded apps that are not SMP aware/optimized and cause cache thrashing can dramatically slow down the app running on multi-processor and/or multi-core systems. Generally this can be resolved by restricting the application to 1 or 2 cores using OS supplied or 3rd party addon utilities, ie: the "START" command in Windows.
2) CPU frequency scaling technology found in newer CPUs over the last decade or so. Many games contain timing related algorithms that may possibly make bad assumptions about the clock frequency of the processor being a static thing. CPU technologies that can dynamically scale the processor speed up or down (ie: AMD's TurboCore and Cool'n'Quiet or Intel's equivalents) can cause these timing algorithms to malfunction in games. That can result in a multitude of potential problems with no absolute pattern. Some problems can include a game just crashing outright, or starting up slow, or other kinds of misbehaviour depending on the nature of how and when the CPU frequency might change and how it might interact negatively with the game's bad assumptions about the CPU clock.
One game that experiences problem #2 here on GOG is "Far Cry". The game starts up but is very very slow to start, with the loading bar hanging for a minute or two before finally proceeding. Eventually it loads and the game seems to run totally fine after though. By disabling TurboCore and Cool'n'Quiet however the game loads up very quickly and runs fine. So those CPU features don't kill Far Cry, but the game's startup/loading code apparently doesn't handle the dynamic CPU clock very well even though it seems to cause no actual harm other than being slow.
Your comments about Gothic got me thinking about this because that game is from a similar time frame where game devs had not schooled up on these new CPU technologies yet or had to deal with them in terms of program misbehaviour.
I guess by now I should automatically think of these obscure problems whenever encountering issues like this with old games.
I'm going to test Gothic again soon and try out my idea first before trying any other ideas people have floated around here in the forums. If I see any positive results I will share the info in existing threads that sound similar here in the forums so spread the info around. If it makes no difference I'll share that too though. It's still good to know about these things though even if it isn't a problem with Gothic - as the problems are rather obscure in nature, so it's good to add them to one's mental troubleshooting tool chest. ;)