PC suddenly restarting after few minutes, has anyone faced this?

Hi friends,

I built a PC about a year ago. Recently it started booting normally but shuts down/restarts after a few minutes of use. Front LED lights briefly then everything turns off and fans seem slower.

I’m not very technical, so I want to understand what might be causing this.

If anyone has faced similar power cycling / shutdown issues with their build, please share your experience or DM me. It will help me a lot.

Thanks in advance!