Windows File Manager not working after Calibre uninstall

[pmgpmg]

I tried using Calibre this summer without success. I'll try again later when I have more time. But after uninstalling it from my Windows 10 PC, my Windows Explorer (aka File Manager) stopped working. I've tried every simple fix. Finally, after restoring all defaults, I was able to get it to start offering me the popup window to choose which app to open files, with Calibre apparently the default choice. I can choose Word, of course, but I really want to get everything pertaining to Calibre off the machine. Can anybody help, please?