Hi Eric. I'm Greg, an installation specialist, 9 year Windows MVP and Independent Advisor, here to help you.
You can install one of these free tools to manage how hard drive space is being used:
https://www.howtogeek.com/113012/10-best-free-t...
I will give you steps to both manage smaller drive storage and perform version Updates on them manually by the most stable method that requires much less space than Windows Update.
First here are tips for managing smaller drives:
https://www.pcworld.com/article/3040404/windows...
https://www.groovypost.com/howto/maximize-stora...
https://www.theguardian.com/technology/askjack/...
As more space becomes needed, you can offload User folders (Documents, Music, Pictures, etc) to another drive as shown in this tutorial, which will not affect speed if C is on an SSD and the other drive is not:
https://www.tenforums.com/tutorials/1964-move-u.... I would not move program files or speed will be affected.
This should make enough space to install Windows Updates. But for now I'd focus on the latest version since successfully installing it will bring along all Windows Updates and also resolves almost all other problems since it reinstalls Windows keeping your files and programs in place.
Install the Media Creation Tool on another PC to create bootable media or download the ISO to stick or disk, transfer it back to the target PC to open the media or click to mount the ISO, right click Setup file to Run as Administrator. This avoids needing the space to download the Upgrade and it's staging files.
http://windows.microsoft.com/en-us/windows-10/m...
If any problems report back the verbatim error and number, then continue with these steps for overcoming Version Upgrade problems:
http://answers.microsoft.com/en-us/windows/wiki...
Another option is to do the the best possible Clean Install in this link which will stay that way as long as you stick with the tools and methods given, has zero reported problems, and is better than any amount of money could buy:
http://answers.microsoft.com/en-us/windows/wiki....
This will give you back all but 15gb of the drive so you can slowly reinstall programs to see how they affect performance, move your files to another drive if possible or offline into OneDrive in the cloud with On-demand access to them only:
https://www.pcworld.com/article/3233488/windows....
There is also an automated Fresh Start that reinstalls WIndows while shedding corrupting factory bloatware, saves your files, but doesn't clear the drive to get it cleanest:
https://www.howtogeek.com/265054/how-to-easily-...
You can also turn off or block Updates if they are bothering you.
There are ways to block Updates here:
https://www.howtogeek.com/223864/how-to-uninsta...
If you want you can set a Metered Connection per the above tutorial, then when ready turn it off to install Updates. You can even wait until the twice-yearly Version Updates to run manually from Media Creation Tool which is a more stable method than Windows Update and includes all previous updates rolled into it.
http://windows.microsoft.com/en-us/windows-10/m...
I hope this helps. Feel free to ask back any questions and let us know how it goes. I will keep working with you until it's resolved
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