Wow, I wish I could give you some sort of help, but I'm at a loss.
Was the file you uploaded a verified epub, or was it a .doc(x)? I ask because sometimes, the simplest fix is often your golden ticket. If it were an epub, then again, I don't know what to tell you. But if it were a .doc then you might want to convert it and then try again.
You say you have a new computer. I have found that sometimes it works easier to have the file in .doc format rather than .docx (just do a file, save as, word 97-2003).
Also, when your book gets stalled like that, it often is an endless circle. You are probably better off starting again. Upload everything as if it was a new book. If they both end up eventually going through, then you can just delete one. However, this can often work to at least get your book up there.
And whatever you do, for heaven's sake don't look at the document or try to touch it after you've uploaded it to B&N. Their program does NOT work and if you open the file, it will often scramble things around. You will end up with an unreadable file that probably will publish, leaving all your family and friends to think you don't know how to use a keyboard.
Author of over 160 children's books.
I have had the same issue with the last 2 books that I tried to publish through NOOK Press. My last eBook has been stuck in limbo for 3 weeks now. I sent 2 emails and had no reply. After the third email that I sent to the support team, I finally recieved an email today that said, "Sorry for the delay. We are still investigating this issue and appreciate your continued patience"
But why is it taking so long? This is the third title that has taken numerous weeks to be published through NOOK Press. I am losing money daily because of this software issue. I don't have this problem with Amazon, Kobo, or any other self-publishing site.