My computer is quite new (less than 3 years old) and was always working really well. I was away from home for 3 days and my computer was turned off and when I came back my computer didn't want to start again.
I tried removing the power cord and holding the power button for 30 seconds and then again tried to start it.
What happens: When I press the power button the CPU fan starts spinning, all lights turn on, and then in 1 second everything dies. If I press the power button again nothing happens, not even this. If I want to reproduce the whole thing I have to remove the power cord and then it "starts" for 1 second.
Nothing is displayed on the monitor.
What can I do? Thank you for your time and answers.
EDIT: I switched the PSU from another working computer and everything was working normally. Fortunately I had to replace just my PSU.