Pc not powering up

Hello, Well, It's been 4 years of my Gaming PC I build for myself. It was my first time so I might purchased some components which you'll tell that I made mistake maybe. Anyways let's fast forward, From these several months I noticed my PC got into so many blue screen crashes like so much...

So, as stated in the Title, my newly built PC won't power on. The first time I built it was like two weeks ago, and I've replaced a lot (basically all) parts since then but nothing is working and nothing, I mean nothing, shows any sign of whatever. No Fans, no Lights, no RGB, no nothing. And I'm...