Dear fvdw
I'm sorry to have irritated you, as I so obviously have. You're quite wrong in your suspicion that I don't read the 'Help' pages before asking questions: I study them carefully, so obviously I must be a complete idiot. All the more need then for patient help, might I suggest?
In the midst as I was of trying to grapple with the idiosyncracies of not just one but two routers at one and the same time, it seemed self-evident that the words "You just need to enable the dynamic IP option in the LAN setup" referred to my router setup. "Dynamic IP" and "LAN" are networking terms are they not? It never crossed my mind that it was the fvdw web interface that was being referenced, so naturally I didn't look there for the answer on this occasion.
It would have been nice if you could have limited yourself to just correcting my misunderstanding, and spared me your disapproval. Wrestling with these technical problems isn't my idea of fun. Life's too short.
Nonetheless I'm forced to continue to ask for your help. I have now restored my LAN setup to the way it was at the outset: one router only (the newest). The immediate result is that I'm back where I started from so far as the fvdw NAS is concerned. I cannot find any way of getting it and my router to talk to each other. As a result I'm once again unable to access the fvdw Web interface and therefore can't carry-out any operations on the NAS via my desktop Windows PC.
My understanding (such as it is) is that a router is supposed to detect all network devices connected to it and automatically to assign them IP addresses within the range it uses. My router refuses to do that in relation to the fvdw NAS and - despite all Jocko's patient help - that's where I'm still stuck:- precisely where I came in.
If any more information is needed to help with diagnosis I'll do my best to provide it. I'm at a loss to know what else it is you think I should be contributing.