Question PC turns on for a second then turns off.

[koopawhohelpswitherrors]

So recently I installed Windows on my PC. The installation went well. However, the CPU got to 100°C. That meant the CPU cooler would need to be replaced, so I did it.

When I pressed the power button, the computer turned on, before turning off a second later.

Does anyone know how to fix this?

 

[koopawhohelpswitherrors]

Update: It now lasts for a minute or so, before shutting off.