SureAI

I put the torches in the four sconces in the black troll cave but the black troll just will not die. (Another strange thing is that he did not chase me as I was putting the torches in, just stood there in the middle... I can't get him to attack me unless I attack him with a dagger). He'll catch on fire, but he won't die, and so I can't get the key. Even after waiting an hour with him standing there next to a torch, all on fire and everything, he just won't die. At the very least is there a way I could add the key to my inventory using the console? I can't find it's refID anywwhere.

Update... just spent an hour (real world time) beating the black troll to death while he was on fire and he just went unconscious, I couldn't retrieve the key from his body even then, and then he just woke up and started attacking me again. Really frustrating...

I'm sorry I can't help you, but maybe Support forum could help you? A lot of bugs are reported there and successfully dealt with by Arvisrend.

PS. I guess it would also help if you attached your savegame.

Thanks Kassandra -- I actually discovered what the problem was, so I'll put it here in case anyone encounters the same problem. I ended up starting a whole new game which worked, and I have an idea why:

When I first got to the stage where I had to get in the trolly to escape the black troll, I pulled the lever but it said it was broken, so just trying to get away from the black troll I jumped up on the cables (where it was supposed to follow me, as I found out with the new game) and ran across that way. The next time (the new game), I tried standing on the opposite side of the lever as I had before (if facing the pit, it would be to the left of the lever) and the trolly took me across and everything worked as it should have as far as the trolly went. Put the torches in the black troll's lair and things worked as they were supposed to. So anyway, point of this is that it seems for this first quest at least, it's important to go through every step exactly as you're supposed to, otherwise things won't work.

Thanks for the explanation and good to hear that you managed to solve your problem.
I will add your case to Wiki notes under Shadow and Light quest. Must have been quite annoying.

i think you need to be standing perfectly on the cart or whatever that thing is. the first time i played through that bit, i was in the cart but the lever wasn't doing anything, so then i thought that i had to get the troll in it and send it off to somewhere else, when that didn't work i started running around in circles looking for a power switch or something, then i figured i might have to jump from the platform into that pool of water, well lets just say that didn't turn out well. when i reloaded that last save it seemed to work fine, well after fiddling with the cart for a few seconds. but, i guess it's a moot point now.