@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).

"lib" folder is in NRS installation folder, which is in C:/Program files/NXT. So just delete "lib" folder from here and you can install new version over the old one.