The reason I'm asking is I've had this running on my Windows 8.1 tablet in the past but now it won't work. The same with NWN Diamond. I've tried alot of fixes and nothing is working. Just wondering if it might be a new version. Thanks.
Planescape and BG 1 still work fine.

I would rather blame Windows update for this. Many old games have problems running on Win 8/8.1.

Thanks. Just wondering what might be the answer. Kinda stumped.

Don't know what you've tried so far, but run BGConfig in the game's installation folder and try several settings.
In the Graphics => "2D & 3D options" section, turn on "Use 3D acceleration" and hit the "Test" button. The test will switch your full screen resolution and display some rectangles. (Also try turning it off, if you're already using it).

You can also try running the game in windowed mode (the option is also in the "Graphics" section, under "Display").