The installation of AVG antivirus ALWAYS fails.

I did all of the things recommended about deleting and resetting things. 

I don't know how to cut out the error message and send it to you, but I wrote
down the text.  Here it is.  I may not have the line endings exactly right,
but I'm sure you will be able to recognize this error message.

Writing config value failed

Severity: Error
Error code 0xC0070643
Error message: General internal error.
Additional message: MSI Engine: Failed to install the product.
@AVGMSI_error 27028
writing config value failed (0xE001003E)
Context: AVG product installation, MSI action failed
Specified file was not found

Severity: Error
Error code: 0xE001003D
Error message: Specified file was not found.
Additional message: MSI Engine: Failed to install the product. [...]

That ellipsis was a clickable link.  It brought up the following text, which
seems similar to what was already displayed.  The order is a little
different, and it mentions "rollback".

Writing config value failed

Severity: Error
Error code: 0xC0070643
Error message: General internal error.
Additional message: MSI Engine: Failed to install the product.
@AVGMSI_Error 27028
Writing config value failed (0xE001003E)
Context: AVG product installation, MSI action failed
Specified file was not found

Severity: Error
Error code: 0xE001003D
Error message: Specified file was not found.
Additional message: MSI Engine: Failed to install the product..
Context: AVG Core uninstallation during installation rollback.

Go online to learn more about this issue

I did go online, but I didn't learn much.  Can you tell me how to get AVG installed?