@lurker10 - text in bold emphasis noted. Thanks.
Looking in my AppData > Roaming >
NXT folder, I have 3 sub-folders:
conf (with .lock; logging properties; and nxt.properties files inside);
logs (with nxt; and nxt.log.1 files inside); and
nxt_db (with nxt.h2; and nxt.trace files inside)
... so what do I need to delete? There is no
"lib" folder that I can see connected to NXT
(I do have a general Libraries folders with Documents; Music; Pictures; and Videos files inside, but no NXT). I assume that the
conf and
logs folders should be on the delete list while the
nxt_db (database?) folder should be kept intact.
I think non-techy NXT adherrents, like myself, might appreciate guidance on this (my operating system is 64-bit Windows 7).

and see if gets your NXT upgraded without manually deleting anything. I have never run NXT on Windows but I read that developers worked hard to enable smooth upgrade on Windows OS with clicking exe and following steps there. Please report if it was successful. If all fails, delete everything related to nxt except nxt_db.