Computer wont boot up

[johnlawress]

Hello everyone. First post ever, hoping somebody can help me out. I bought a self-built computer last year with the following specs. Im only a bit familiar with computers, so the information i can provide may not be totally precise.
256gb ssd
GTX 770
32 GB RAM
Intel i7 processor
ZT series 650W power supply

The half a year or so theres weren't any problems at all. Then it started to occur that when i tried to turn it on, the lights would go on as usual as well as the fans. The monitor did also register something, but nothing would show up on screen whereafter the monitor would switch between hdmi and analog. In the beginning i could resolve it by trying again a few times. Slowly it started to happen more and more often and now it wont boot up at all. I've checked all the essential parts and everything looks fine. I suspect somethings up with the power supply, but i've got no way to confirm this. I've also lost the number of the guy i bought it from so im basically pretty ________. I just hope somebody can give some pointers as to where to problem might be located. Thanks in advance! Please let me know if i need to provide some info or pictures

[Geek-9pm]

johnlawress,
You will have to open it up and try some things.
Here is a guide:
https://www.computerhope.com/jargon/t/troushoo.htm

Turn off power and remove the electrical main cord. This is important.

Try to reset power cables tat come for the PSU.. This means you remove the cable and push it back in. Do it two or three times. this 'wipes' the contacts and cuts oxidation. Sometimes that works. It is worth a try.

Also, disconnect the DVD drive from power and data.

Put electrical main cord back into the wall and try to start up again.

Here is an updated CH link:
Why won't my computer turn on?

[patio]

It ain't the PSU...thats a solid unit...good choice.

However even good ones have a fail rate...borrow a known good one and swap it in...you'll know overnite...