So I can't do any research. If it's many years old, you find you replace parts but we always restore to factory first to see if it's a damaged OS issue.
I have a Gateway All-in-One PC. When we leave the computer idle for a while and come back to it, when we wiggle the mouse to turn the screen back on the computer shuts off.
There are no power saving options set.
The computer has been cleaned to make sure it was not overheating and it isn't. It works fine even if we use it for hours and hours on end. But if we leave it for 3 or 4 hours and then come back and wiggle the mouse to turn the screen back on it just shuts off completely. No power at all. Its like someone pulled the plug.