Question PC flickering and not starting

[Themoniter61]

I was away on vacation, come home and go to turn my PC on after it was off (with the surge protector off as well) for about 12 days.
It all boots up fine. Works for less than an hour, I go to to enlarge something on youtube (dunno how relevant that is) and then the whole thing crashes.

I have an MSI Z87 Gaming (MAtx) so the power button on the Mobo still lights up but when I push it or the case button nothing happens.
I go to turn off and turn back on the PSU and it will give a flicker (fans move lights come on) for a second before going dark again and then buttons do nothing.

I've already tried removing the GPU and starting it again but it's all the same. removed RAM sticks and same issue. Haven't tried removing CPU yet.

I assume it's the PSU for two main reasons:

1. The light on power button and OC buttons for the mobo stay on (if the mobo was cracked or otherwise fried I assume it wouldn't function or trigger the lights, fans, etc no matter how briefly).
2. It is an old ass off brand PSU that has no business still running about 15 years after I bought it. (It's an Ultra Xfinity 600 watt PSU https://www.amazon.com/Ultra-XFinity-Switching-Supply-ULT-XF600/dp/B00FJNTHVG ). It certainly does not help that I was running it in a Corsair air 240 with ahem less than optimal airflow in the PSU chamber).

Is there any other troubleshooting steps I should take that I haven't already? I was just gonna run out and get another PSU and see if that fixes it.

I just got a new 1660 TI and was really excited to get it going!

Thanks for the community help!

 

[Phillip Corcoran]

"I was just gonna run out and get another PSU and see if that fixes it".

Then what are you waiting for? It has be worth swapping, especially considering the age of your current one.

 

[Themoniter61]

It was indeed the power supply. I'm only shocked because usually fixing this stuff is never this simple.

Replaced it with a Corsair RM550X (they have a ten year warranty so I'm covered till 2029) and in addition to the PC working, it is now practically silent when not under load.

Now can't wait to pop in my new 1660 TI.

Thanks!