Sorry for not responding, your posts didn't show up since you didn't respond to me directly . . . =)
@laffer Make sure you also right click the game shortcut, click Properties, click the Compatibility tab and check "Run this program as an administrator". I uncheck "Run this program in compatibility mode for" to start with, especially with Win 7. If the game doesn't work then try the compatibility modes one at a time.
Also check to see if your firewall is not throwing up consent dialogs behind the game window by Alt-Tabbing out of the game. If it is click "Allow" and it will stop blocking the game. I use Comodo and it does that often. I would open a help ticket with GOG as well.
@Thunderstone I don't know of a program like AMD's for intel but . . .
There is a program that sets affinity to a single core if you have a dual core system.
Here is a link to a post that gives an example of how to change the game shortcuts target path on the Shortcut tab. There is also a link to download the program. It is free and small.
Basically, you extract the RunFirst.exe and put it in a folder. I put it in a folder under C:\Program Files\Gog.com\RunFirst since I use it with a couple of GOG games and this allows me to just copy and paste from one shortcut to another. You simply take the path to the program "C:\Program Files\Gog.com\RunFirst\RunFirst.exe", add quotes at the beginning and end and insert it into the target path of the game shortcut BEFORE the game path. You need a space between the two paths.
The path for Divine Divinity looks like this -
"C:\Program Files\GOG.com\RunFirst\RunFirst.exe" "C:\Program Files\GOG.com\Divine Divinity\div.exe"
You would have a similar path except using the path for the location of the Runfirst.exe on your system and the path to the Septerra Core exe that already exists in the shortcut. Attached is an image showing where to insert the path to RunFirst in the game shortcut. Because the shortcut cannot be sized, I can't show the whole path. Anyway, RunFirst path first, encased in quotes, space between the two paths, game path as it exists encased in quotes.
If you do not have a dual core system - DO NOT USE THIS, it will not help.
This is not the same as the AMD Dual Core Optimizer, it just sets the affinity to a single core which greatly improves some of the older games ability to run on a multicore system. A sound problem is a good indication that RunFirst might help your game.
When the path is correct, upon clicking the shortcut, you will see a small DOS window followed by the game opening. It only sets the affinity for the game and closes when the game closes.
Hope this helps . . . =)