Yeah. as you go through so much getting it to boot. When done turn the monitor off and just leave the case on. It's not like it's a monster rig with a huge energy draw. Another thing you can try is once on, wiggle all the cables and the connectors a little and see if by pinching and moving the power cable you can see the system flicker or turn off, then yo know it's a bad cable or connector? A replacement power cable is very cheap and maybe worth trying, likely you have one around or worth having an extra.
Here's a USA style cord:
Link Depot Model POW-6 - Newegg.com
I hate to say this but Damn none of us thought about the obvious lol. Good catch Linnemeyerhere It's possible it could also be a bad plug on the power strip. I just had one go south on me this morning. It worked fine all this time then this morning I went to turn on a machine I was testing and no boot. I spent 20 minutes inside the machine before I pulled out my voltmeter and tested the power cable. No power, moved it to a new strip and good to go. Only one plug was bad but I tossed it anyhow. I don't like fire hazards. :shock:
I might suggest bypassing the strip one time to see if it boots.
Real

moment for me though. Time to remember some of the basics lol.