Windows won't download updates or MS Store items

2018-09 Update for Windows 10 Version 1803 for x64-based Systems (KB4100347) - Error 0x80070015
018-12 Cumulative Update for Windows 10 Version 1803 for x64-based Systems (KB4483234) - Error 0x80070015 blah blah blah.
It refuses to download. I’ve downloaded some stand-alone troubleshooters from the windows help pages and they purported to fix a corrupt windows download database.
But when I tried to update again, I get the same errors.
So, what should I do? Some people say I should uninstall the updates and start again. Some say I should revert Windows back to the initial install.
The trouble is, I have a lot of media, mostly old movies and songs I’d like to keep without going through the expense of buying external back up hard drives.
Of course, I will back up my critical data, but I want to fix my computer without having to lose the data on my nonsystem partitions.
I have two physical hard drives in my computer. I think I can move all media to the other physical hard drive. If not, could I still be able to repair or even reinstall windows and still preserve the data on my non-systems partitions?
Forgive me. I’m a part time computer geek.
I’d like an easy way to fix this update prolem.
If not, I would like to know the best way of fixing it either from rolling back the updates or just reinstalling windows and keep my data on the nonsystems partitions intact.

Yes, the Windows are legally mine. I’ve got the License key and the usb stick .

That update is a standalone targetted update, it updates the microcode on some, not all, CPU’s. You should find out if your CPU is on the list that it updates as it may just be a bug and your CPU isn’t supported. Either way, it’s not what you would call a critical update and you wouldn’t notice any difference or stability increases if it were installed anyway.

Also saying that, if you have your motherboards auto update software installed, it may have already downloaded and installed a different variant of the update that the motherboard manufacturers have modified specifically for your motherboard. Windows won’t see it as a modified version of the update and try and install its own, but when it comes to checking for the version it may be slightly higher and fails.

It says I’m missing critical updates. And My Microsoft Store is not working. I guess, I have to do a massive backup and reinstall windows. I really don’t want to do this.

Have you tried going to Microsoft’s website and downloading the updates (outside of windows update) and manually running them?

Can you do me a favour?

Press start, begin typing sysinfo

And when System Information comes up, press that.

Take a Screenshot of your System Information and post it here. Want to see which windows 10 you are using