Just a note for people, if you crash during a render you may end up with corrupted temporary files within windows user temp. I was trying to restore a old hard drive from my desktop and it went through and removed over 20 bad PNG images and TIF images from folders for /Terragen/. These can amount, like in my instance to a bad sector that needed remapping.
So if you do crash while rendering you may want to run a chkdsk /r to cleanup before files start piling up. I wasn't aware of this and had probably 2 years worth of TG crashes and corrupted files which isn't good to carry around.
The hard drive is toast, but I doubt from TG, there was lots of Windows update files corrupted (probably crashes) that lead to a lot of remapping to the point a fresh copy of Windows 10 is triggering start up repair and going into a restart loop. My luck with being poor and second hand or hand me down hardware is always a fun tale.