How to stop old Sony Vaio PCG-61111M laptop from randomly shutting down
I was installing Windows 10 on an old Sony Vaio PCG-61111M laptop and the installation went smoothly. I left it unconnected to the internet for awhile and did some other things. When I came back it was still turned on and I connected to the wifi and made sure I could connect to the internet via a web browser and also checked that the Windows license was activated.
I then walked away from my desk again and got on with other some other things. When I came back the screen was black and the laptop didn't respond with movement of the mouse of tapping keys on the keyboard. I switched it back on via the on/off button and it booted back into Windows. I checked the sleep settings but there weren't any. This surprised me a bit. The only setting was the screen turning off after a period of 10 minutes inactivity.
Then a few minutes later the laptop just turned itself off! Now I was getting a bit worried. What was going on. I turned it back on and it booted up fine into Windows but then after a few minutes it switched itself off. A Google search into the problem indicated that the graphics driver needed uninstalling and reinstalling. I did this although I was a bit sceptical because the only driver was a Basic Microsoft Driver. If this was the cause then there was no hope.
I then had a brain wave. When the laptop wasn't connected to the internet it seemed to be fine. As the computer wasn't able to go to sleep I remembered that wifi adapters have a Power saving setting. I turned this off and the problem was instantly fixed.
See How to turn off power saving setting on WiFi adapter base article for details on how to turn off this setting.