Trying (unsuccessfully) to repair Windows Security. Anyone kindly help me?

Nice. I followed the instructions to the letter - all seemed to go as you indicated, but even after a reboot that Avira key, {B97A4A5B-EBEE-B18C-3CAE-9F944A005B16}, is still there in the registry Provider/AV key. It disappeared in WBEMTEST (and is no longer there when I run WBEMTEST again), but the registry entry has remained, as I say.

Did you reboot after deleting them?

Do you still have any of these folders on your system?

C:\Program Files\Avira
C:\ProgramData\Avira

Yes, I rebooted. No, I have neither of those folders on the PC.