To me it looks like you are losing or lost your DVD drive, if I am understanding "The DVD drive chatters away incessantly ...".
I bought a second DVD Drive and from that I can install FSX_MS ever since. My first one got the chatters half way through installations not from the beginning like yours but I didn't wait and bought the second one instead. Dirt cheap nowadays.
Also, your DVD disks for FSX_MS are gold now. Do not jeopardize them for any reason.
Sorry for the bad news and as always, I can still be wrong. Your call.
Cheers,