Why is my computer shutting down automatically?

When I play a game about 30 min the game and all the programs close and windows gives me a message:shutting down, please help
It’s not overheating or a virus
I run my computer in windows 7

need more info but here is random thing.. do you have automatic updates and do you at all times keep computer active during the 30 minutes of your game?

My computer…

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