I'd guess the cpu is getting too hot or you may have corrosion on the mainboard (ram or ram slots), or the ram sticks are failing.

It's a shame when hardware goes this way, oxidation is like a cancer, it slowly spreads.

I've lost expensive hardware (motherboard, graphics card and ram) this way living in a seaside paradise.

memtests, short but deep...

Test 2 [Address test, own address]

    Same as test 1 but the testing is done using multiple CPUS, if applicable. 

Test 9 [Modulo 20, Random pattern]

    Using the Modulo-X algorithm should uncover errors that are not detected by moving inversions due to cache and buffering interference with the algorithm. 

I also tried Peppermint-Devuan and here is my post to them:

Wonderful birthday present - lost internet for most of the day!  OK!  I now have a new carrier.

I used Synaptic to dl firmware-realtech, finally found where Synaptic placed it and put it on a USB stick, fired up the Peppermint (Devonian) Installer, attempted to install the firmware - deb told me it was already installed!

When I try to add WiFi, whether through Add WiFi (only Ethernet is active) or clicking on my WiFi network, Ohh! My hand drawn pop up got edited out of my OP - something about not able to add.  Here it is from Dev1 Galay:

Connection add failed
failure adding connection settings plugin does not support adding 
connections
		[ Close ]

( The Pop-Up title is different on Pep but I was getting the same thing with installation from Dev-1.)  Also, the installation screen will frequently go to a black screen  and I have to Power Off and start over.

Unfortunately, the installers no longer have a memory check option.

Unfortunately, I guess I'll have to give up Devuan and stick with PeppermentOS on that machine.

Bruce

you won't be able to use your old / or /usr directory because it will cause conflicts, I think with linking. But...

during install at the partitioning stage, if you want to use your /home directory... when at the fs stage (partitioning, filesystem spec and formatting)

select your fs type, and mount point (/home) but do not select "format the partition". That should get you back to your home files after the install has finished.

If you have multiple drives and swap spaces, go to the other drives and deselect those swap spaces by selecting "do not use this partition" for those swap spaces.

This can help to reduce shutdown time and cross-contamination, but also stops the installer from issuing new uuid's for those swap spaces, which can mess up the other installs booting procedure (can't find swap).

About wifi, I have the firmware file for my wifi/bt card on a flash-drive, that I insert just before starting the install program, it may or may not be your problem.
Yours may be, firmware-realtek, unpack it and place the "iwlwifi-9260-th-b0-jf-b0-46.ucode" (in my case, intel wifi) file on a memory stick.

All the best.

Although the problem may be that my WiFi is a RealTech module.

Bruce

It won't let me start WiFi:

Connection add failed
failure adding connection settings plugin does not support adding 
connections
		[ Close ]

Now to kook through the derivatives again and see which promises to match my interests.

Thanks again for all of your help.

Bruce

Maybe you simply need to use su - to get root access instead of simply su. The difference is the path.

The fact remains that PeppermintOS, a Debian derivative, couldn't find it.

Bruce

/usr/bin/sha256sum is part of coreutils, which is an Essential package in Debian-based distros.

The only time I verify downloads now is when I have difficulties with it.

I had this message written about 4 hours ago when I Iost internet.

Now that the net is back, I'll see about downloading again.

Bruce

change the uuid from the new /home to your old one... and save it (you'll need root permissions to do most of this).

Before you reboot, rsync your new home to your old home to refresh any start scripts...

rsync -avh will only over-write with newer files, leaving the rest intact.

I did this just last week, and it works.

welcome to hawaii

However she well understood the concept difference between "partition" and "file system" (on the partition). Therefore she was able to reuse the partitions where she had had a "/"  and "/usr" filesystem on before for a new installation. Then  she cleverly opted for the approach to hook up that "/home" filesystem as a post-install hands-on iby editing of "/etc/fstab" as well as removing the content of that newly installed "/home" subtree.

They are clever in Hawaii.

I believe there MIGHT be a way but I'm slower than the tortoise and am not comfortable with the more expert installations'

My first successful Linux install was VectorLinux, a Slackware derivative.

Any possibilities to get 'freedom'?

Bruce