Setting a custom Resolution and refresh rate is generally problematic in and of itself, it was more a question to see if the problem could be related to such.
As for enabling Window mode, you need to either find or add the line AllowWindowedMode=1 to your NWN.ini file in your Neverwinter Nights folder somewhere under the heading of [Display Options] and once the line is added it is possible to enter by pressing the Alt Key and Enter key together.
INI file should read something like as follows under the Display Option's heading.
[Display Options]
AllowWindowedMode=1
Disable Intro Movies=1
BitsPerPixels=32
RefreshRate=60
Tried a diffrent screen (and diffrent model) and that seemed to work. only question then is why did it work before on this one and why does the problem go away from time to time. still would like to try out windowed mode and custom res if anyone can explain how to do it for me. Cheaper then buying a new screen.
Most certainly cheaper, as I said most of them were basic question's to simply get a better idea of what has been tried and some more information on the problem itself.
The fact that with the same model screen you get similar results, however with a different model it appears to work fine is rather interesting that would generally leave me thinking such is likely an issue with the Monitor's driver and it needs to be reinstalled or possibly a setting associated with that particular monitor's settings.
Test out Window Mode, see if that at least helps out while you're running NWN in a window.
Double check any setting associated with your monitor, resolution and refresh rate, relating to either Nvidia' or Win7's desktop settings.
On principle I'd suggest updating your graphic's drivers.
And if you're Tech Savy or have a friend that is, reinstall your monitor's display driver.
These are merely suggestions on what could possibly help.
I am trying to think of other things to recommend trying, but I'm coming up with a bit of a blank myself beyond testing the above, with any luck somebody else will chime in with assistance based on experience as I can't say I've ever experienced this issue.