Update in case anyone wants to know.
Well went back to playing around and nothing seemed to work. So on a whim I found a USB stick that I had put Ubuntu on, you can boot from it and try or install...
so installed it, and for now the machine runs fine. Does not shut down or power off or power save like it did. Got to think something in the software was buggy. Same monitor, keyboard etc. So now I got an extra machine, running a different OS but it can do what I need.
Coming back to where you started is not the same as never leaving