Hi Andrew Hollstein
Welcome to Microsoft Community.
Based on your description, I understand that you tried memory testing but only completed 21% of the first phase after a long time, and I understand very well how you feel!
The situation seems to be stuck at 21% of the first stage. In terms of the principle of memory testing, memory testing is to test for bad spots in the memory by constantly writing and reading data.
But I will give you some other ways to try to see if you can complete the memory test first.
Option 1: We try to re-run the memory test, but we try a different scenario.
(1) Click “WIN key” to open the search bar -> type “Windows Memory Diagnostic” and open it with administrator privileges.
(2) Select “Extended Test”.
(3) If running it for a long time causes problems, try reducing the number of passes or selecting “Standard Test” instead of “Extended Test” to see if it completes successfully.
Option 2: We try to run the memory test in safe mode.
Safe mode uses only a limited set of files and drivers and can help us reduce isolation problems.
For safe mode you can refer to: Windows startup settings - Microsoft Support
Option 3: There are actually third-party memory testing tools with different underlying principles that provide more comprehensive and targeted insight into memory issues during operation.
And the tools dedicated to memory testing are more powerful.
Unfortunately, due to community rules, I can't recommend third-party memory testing tools for you.
However, you can search for them through search engines and try to download and use them.
Please note: Please use a memory testing tool with a large population and high security.
Option 4: On a hardware level, we can actually try to take apart the laptop.
Remove all the RAM and wipe the gold finger part, then insert only one RAM stick to see if the computer works properly.
Repeat the above steps until all memory sticks have been performed.
On top of that, I actually had a similar problem when I was a kid playing with my grandpa's computer when it was stuck at 21%, and have had other users experience this as well.
Generally speaking, there is a high probability that the memory stick particles are damaged or have bad dots, so the memory stick is stuck at 21%, unable to write/read data, and ultimately unable to perform subsequent read/write operations.
I sincerely hope that the above solution will solve your problem. Please feel free to contact me if you have any problems or still can't solve them. (Photos related to the question would be great!).
I look forward to hearing back from you.
Best Regards
Arthur Sheng | Microsoft Community Support Specialist