Question PC still not booting after replacing mobo + psu (video attached)


Sep 2, 2014
I had an issue with my PC a couple of years ago after it decided to stop working one day right in the middle of uni deadlines (sh*t!). Long story short, i needed something urgently so replaced it with a laptop, and never bothered to go back to it until now.

Fast forward until now, i was convinced it was either an issue with the motherboard or the PSU; I replaced the PSU when I first had the problem, but didn't solve anything. I replaced the mobo yesterday (with the new + unused PSU inside) and still no luck. The only thing it can possibly be now is either the CPU or CPU cooler (I've read that it won't boot and switches off automatically if the CPU isn't being cooled).

I have attached a short video to show exactly what is happening. In other videos I have seen which demonstrate an overheating CPU, the PC will at least boot for a few seconds/minutes before it overheats and shuts down. So I'm guessing that the CPU must be dead. I'd just like to get some opinions of those with more experience, or anyone who might be able to elaborate on what is happening from the video. I also don't have access to any spare parts, so if anyone could tell me how to test either of these theories without replacing any parts I would be very grateful!



Retired Moderator
...have you verified whether you can short the pins on the motherboard to turn it on? It's possible (although unlikely) that the connector to the power button is defective.

And what are your full system specs (including what you replaced)