Hopelessly lost and infinitely embarressed Options

[worksfortheman]

I downloaded and got nej going. I've got my party through the severed hand and cleared out the entire place. I handed over all of the pieces of machine I found, but I think that I'm one short. I read the walkthrough, and have literally spent over 4 hours walking and rewalking through every room in the tower, holding the tab button and searching every single container, and I can't find the missing machine part(s). I've cleared all the tasks- from rebuilding the garden to freeing the souls of the soldiers. I've also tried retracing the steps of the walkthrough. At this point I'm desperate to move on. Is there any chance anyone knows the item codes for the machine parts? or the area codes/locations of them?
(setting aside those possibilities, given the chance that I had picked up all of the machine parts and then foolishly dropped one to make room for a two handed sword +1 and its somewhere I stand no chance of finding it, will I screw up my game if I movetoarea back to kuldahar and go through Arundel's portal without officially finishing the hand?)
Thanks for any help, and yes I feel like quite a fool...

[worksfortheman]

I handed over each of the pieces as I got them- if I remember correctly I only got three. The one you referred to was the first one I got- I'll do another sweep, but after killing everything in the tower and the lower levels, I've been to every room 3+ times going through every container. I'm not exaggerating at all when I say that I've spent 4 hours going through each room searching for the last piece (at first it was therapeutic because the total lack of threat was a nice contrast to work stress, but at this point I'm at my wit's end and wondering if it'd screw up my game to say forget it and warp back to arundel's portal and move on)... (on a related note, the toughest part is that after playing dragon age origins the past couple weeks, I find myself highly nostalgic for the deeper spell-casting of BG2).