I read over the readme file and from your posts I gather that you have as well. You obviously meet the system requirements. I found this remark " If you are experiencing difficulties with launching the game post-install, try rebooting your computer and try running the executable again - this seems to work in the majority of cases." Have you tried that?
At this site which I found in the readme--
http://www.atarisupport.com/ I found the following info:
"Black screen (when starting the program)
Disable 3rd party applications running in the background
Background applications can be either closed temporarily or disabled. If they are temporarily closed, they will start again when the computer is restarted. If they are disabled they will need to be manually re-enabled to run them again.
To temporarily close any extra applications and services running in the background in Windows XP:
1. Hold down the Ctrl+Alt+Delete keys simultaneously on your keyboard.
2. This will bring up the Task Manager. If it brings up Windows Security, click the Task Manager button.
3. Click the Applications tab. This will list programs currently running on your system
4. Hold down the Ctrl key on the keyboard and click each program to highlight it.
5. When all the programs are highlighted, hit the End Task button. If you get any messages that state the program is not responding, hit End Task again.
6. Now click the Processes tab. Click the bar that says User Name to sort the list.
7. Click on any of the processes except EXPLORER and TASKMGR that have your login name in the User Name column. Then click End Process. Click Yes on the Task Manager Warning. Repeat this step to remove all processes that are under your login name except EXPLORER and TASKMGR.
This should temporarily close any conflicting background applications. These applications will start up again when you reboot."
"Black screen with sound (when starting the program)
Having outdated video drivers install or nor having your monitor setup correctly generally causes this.
Set up your monitor
To setup your monitor properly in Windows XP:
1. Right click on the Windows Desktop where there are no icons. Click Properties in the pop-up menu. This will bring up the Display Properties.
2. Click the Settings tab, then the Advanced button. This should bring up the properties window for your video card.
3. Click the Monitor tab.
4. Make sure that your specific monitor model is listed under Monitor Type. If it is listed as a Standard Monitor, PNP Monitor or something similar, check with the monitor manufacturer for the proper drivers. These drivers are usually available on the manufacturer's web site.
Also make sure that your monitor is capable of the Screen Refresh Rate. Your monitor documentation should list the appropriate settings."
Otherwise the only thing I can suggest is phoning their tech support or seeking help on a fan NWN site. The site I like is The Amazon Basin's. The NWN site at the basin is not high traffic, but very friendly with helpful knowledgeable folks.
Nwn forum Good luck! Keep us posted.