Anarchist_Peasant: it didn't make any difference.
The
Windows 8 Performance "Patch" (works in Win 7 and 10, as well) can help with graphical issues.
Did you try Software mode, rather than Direct3D?
In the install folder, try right clicking on the div.exe program file, select Properties, switch to the Compatibility tab and try a Win 95/98/ME compatibility modes. That can help with the screen being green. You could also disable desktop composition and check 'Disable display scaling on high DPI settings', if applicable.
Try rebooting, if you haven't done so already while troubleshooting. I will eventually get tha problem with dark textures and rainbow colours indoors and at night on my current system if I leave it on continuously (days/weeks), but can fix it by rebooting.
In the Divine Divinity install folder, edit the config.div file (in Notepad, or other text editor) and add/edit the line rgb 555 and change the number to something else, like 565. If the line isn't there, go into the graphics options and change the gamma, or something, and it should be added, or you can do so manually (just not as the last line in the file, as the game expects that line to be blank, and ignores it).
Check for updated graphics drivers. One person with the rainbow texture problem fixed it by the configuration file edit, then a driver update caused it to happen again, and the next update fixed it.
Try resetting your graphics driver's 3D settings to default (right click an open area of the desktop to start the nvidia Control Panel or ATI Catalyst Control Center).
You can try using the disk version of the configuration program, to set the game to run in Direct Draw mode. Rename or move the existing configtool.exe and NlsEng.dll files in the install folder, and extract the disk versions from
this zip file.
Note that this will also reset the game resolution to what the disk version supported, but you can manually edit the config.div file to change the resolution back.
Alternately, maybe WineD3D would work better than Direct3D; see the topic
Windows 8 slow graphics problem fixed using WineD3D.
There may be additional suggestions in the topics below.
Graphical Issue, Indoor textures turning black? Indoor graphics issues Rainbow Shadows and Uncooperative Interiors Software/Direct 3D Issues Game screen greened out