Yes, I have done a few things already, including memtest. I'll copy from the forum:
The things I have tried:
Updating my BIOS.
The ISO I downloaded has been md5 checked, all fine. I have also tried 2 other ISO files from 2 other mirrors - same.
Three (3) USB drives to install Mint, ranging from 8 GB to 24GB.
Installing with or without multimedia codecs.
Turning on secure boot before install (I was desperate, found a forum post with a similar error message, later I found out that it was for a different reason).
Turning off secure boot before install (I found a different forum post where the exact opposite was recommended - later I found out that it was for a different reason).
Installing in compatibility mode.
Offering a sacrifice to Xebeth'Qlu, tormentor of souls.
Running gparted before install, deleting the previously half-installed partition, formatting it myself to ext4, then running the installer.
Splitting the aforementioned partition into a 16GB swap partition (I have 16GB RAM) and leaving the rest of it as ext4 (mounted at "/").
Running chkdsk -f on the SSD containing the MBR+Win10, then rebooting the PC twice, according to one of the error messages in my post below (then trying to install again).
