I know "memtest86" was before "memtest86+", but memtest86+ is a
successor
I just found my system rescue disk, booted it, entered the memtest86++ and see lots of FAILUREs (I have 128 Gb so that may be why it's been hit and miss).
I'm trying to see if a log is or can be generated for my warranty repair.
Thanks to all who gave advice!
-Tom