Hi there,
0x80070643 error occurs if .Net Framework is corrupted in your PC. To fix the issue, try to run the .Net Framework repair tool and check if that helps.
https://www.microsoft.com/en-us/download/details.aspx?id=30135
I would also suggest you try getting the updates manually and see you can install them.
You can get the updates by KB (KB2635973 ) number from the below link
https://www.catalog.update.microsoft.com/Home.aspx
You can also temporarily disable all your antivirus and try installing the updates.
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