0nomaly: Ok, now I:
chose "allow all this page" in no-script so that nothing it being blocked (I had already allowed GOG before. No-script had been blocking only Twitter and Facebook, which I don't know why those are showing up on GOG forum pages anyway.)
deleted cache
deleted GoG cookies again
Still, same result. Sign Up/Login at top when logged in. Endless cycle of get asked for password when try to send pm, so still impossible.
Apparently GOG's site absolutely hates Firefox with a fiery, fiery vengeance.
Let's try IE as that's the only other browser installed...
No problems. At all. Well, problem solved but certainly wasn't expecting that. Not a huge fan of having to use a different browser just for one site either but at least things are functional now.
I'm also a little confused about something. "Start Conversation" is GOG's version of a pm, right? And someone doesn't have to be online when you send something in order for them to see it, right? It's just confusing cause it looks like that goes to a chat room.