Thank you again for all of the time and hard work you put into solving my problem. Annoying popups are still gone.
I am following your other advice to continue being proactive and in the meantime was able to update my BIOS with no issues; no other blue screens yet - so keeping fingers crossed there! Your solution for getting the files hidden again also worked perfectly.
I can not tell you how happy I am to have come across this forum - and again for your expertise. Thank you!!