Hi Redhawk 1,
error 0x80073701 usually indicates that there is a problem with the Windows Component Store, which is a database of system components used by Windows Update.
Since you've already tried several troubleshooting steps, I would recommend running the System File Checker (SFC) tool to scan for and repair any corrupted system files. To do this, open an elevated Command Prompt and type "sfc /scannow" (without quotes) and press Enter. This process may take some time to complete, so please be patient.
If the SFC tool doesn't resolve the issue, you can also try running the Deployment Image Servicing and Management (DISM) tool to repair the Windows Component Store. To do this, open an elevated Command Prompt and type "dism /online /cleanup-image /restorehealth" (without quotes) and press Enter. Again, this process may take some time to complete.
If neither of these steps work, you will need to consider a repair installation.
Hope it helps.
Regards,
Lei