Is this through Steam or Arc or the original discs or has it moved to NWN2 or...

I played when it was the original discs. I have no idea if my computer can handle NWN2.
You need a copy of the original NWN, with a valid multiplayer CD Key. If you still have original discs/keys, great. If not, you can buy a digital copy from GoG. Just make sure you request a mutliplayer key from them once you do, as the default one they hand out is a generic.
If you have original discs you shoud probably still have valid keys for NwN1.
