Ram / memory damaged / defective?

Have a Zorin Os / Windows 10 dual boot.

Had quite a few Opera tabs open and a few other programs in Zorin Os. Then wanted to start Minecraft and then could not move my mouse. After a while I was able to move the mouse pointer and tried to close the other programs. This also worked but after I wanted to play Minecraft, my PC hung up completely and I had to restart. Something similar happened in Windows, but I didn't have to restart it completely there.

In addition, Zorin Os shows that I have 7920 mb free RAM in Windows, but 8404mb. However, this is constantly changing in Windows. Sometimes I have 8192 mb ram times 8404.

I have installed a single 8GB ram stick in the PC that has been in there for 4 years.

Have already made a mem (?) Test but it didn't show anything.

This is not a hardware error, because I would have simply knocked it out of Windows and restarted it immediately or got stuck with the BIOS or made a complete freeze.

A lot of software is a lot of potential for errors. It is better if you don't see too many of the windows.

Of course, the storage situation changes. If you then look into the task manager and do the math, that's right.