How to fix error 0x800700d8 (Nothing else worked)

If none of the other solutions to fix this error and update Windows worked, what you can do is to reinstall Windows, and install the upgrade before you install any other programs.

Before you reinstall Windows, make sure to backup all your personal data stored on the computer (photos, music, videos and other invaluable documents) to an external hard drive, or to online backup solutions like Google Drive, OneDrive, and more, to avoid losing them in the process.

If you feel insecure when it comes to reinstalling Windows, do check out the don't know how to install an operating system guide on how to (re)install your computer's operating system, safely.

If none of the other solutions worked, perhaps your computer's BIOS (Basic Input/Output System) needs to be updated. As this is a tricky process that requires skilled hands, it would be best to take your computer to a repair shop.

If you want to update Windows on your own, then you need to download the latest BIOS version from your computer manufacturer's website and install it, following the instructions found on the website of your computer's manufacturer.

Note: If you use a desktop computer, you need to search for the BIOS version on the motherboard manufacturer's website.