Wait, how did you get that far? I had to make some changes to the DMA code to make it not get a stop 7b when booting from the floppies. Anyway, I think that it's working in the last screen but the display controller autodetect failed.
I used "winnt /b" from DOS to skip the floppies and boot from HDD.
Glad to see it working, NT was a bit of a pain to install even in my actual PC-9821Nw150 (it has an additional Trident graphics chipset, and finding an appropriate driver for that was pure insanity), so getting it to work in an emulator is quite nice.