been trying to play NWN diamond with my sister, keeps saying cd key is already in use.. downed the CD Key changer, save it, still nothing. gog is NOt a co-op step up it seems.... any help (with clear instructions plz, lod person here hee ) would be GREAT. :)

Click on the game in your library. Select "More". Then "Serial Keys". Here you can find CD Keys for your copy of the game. Unfortunately there's only one, so if you want to play with someone he has to buy a copy as well.

Did all that, my sister bought it on gog as well, and got the cd key as well, still says that it is in use. :)

Just to be sure, did you change the CD keys? You can do this using the Multiplayer Key Changer. It's found in the menu start or in the GOG Galaxy. If you've already done this and the keys don't work, then contact GOG support and they should provide you new ones: https://support.gog.com/hc/en-us/requests/new?form=technical.

no idea how to do a DXDiag window, so pretty much scrapping GOG co-op options.

On Windows, press the Windows logo key + "R", type in "dxdiag" and press Enter. That will open the DXDiag window. Wait until the green bar is full, then click on "Save all information", choose where to save (e.g. on your desktop), click "Save". In your support request, click "attach file", navigate to the place where you saved the dxdiag file (e.g. your desktop), select it and press Enter.