Computer turns on then off then on again everytime why?

[Superclarkey]

Everytime I turn on my PC which is only about 6months old. It turns on then turns itself off after a few seconds then a few seconds later turns itself back on again. Can anyone help me is this a big problem?

[Lil_Boy_Blue · Accepted solution]

Hi
PLEASE POST ANY RESULTS.
First:- Turn off the computer, press and hold the PWR button for 4 seconds.

Then - Leave only keyboard and mouse connected, disconnect all externally connected
devices such as Docking Station, USB storage devices, displays, and printers.
Unplug the AC adapter from the computer.

Next - Press and Hold the Power button for 15 seconds to Hard Reset.
Rinse and Repeat; Re-Connect the AC adapter.

NOW begin checking/testing/proving the Hardware is fit for purpose.
Power on your PC, press ESC (repeatedly), then F2 at the prompt.
Choose System Tests (Fast Test does a 4 minute hardware check).
AND/OR
HOW DO I USE DIAGNOSTICS?

HP PC Hardware Diagnostics is a Windows-based utility that allows you to run diagnostic tests to determine if the computer hardware is functioning properly. The tool runs within the Windows operating system in order to diagnose hardware failures. HP PC Hardware Diagnostics Windows comes pre-installed on new HP computers, but if not on yours, download here:-
https://www8.hp.com/us/en/campaigns/hpsupportassistant/pc-diags.html

https://www8.hp.com/us/en/contact-hp/ww-phone-assist.html

If there is a fault/problem under warranty contact HP in your region.

[Superclarkey]

hey lil boy blue,

I did all your things but not in that order so I did the 4 second thing and the diagnostic tests before writing the original post they all passed and didn’t help. I then spent ages online speaking to an advisor whose fox didn’t help and as you can imagine I lost the connection as I have to turn the PC off to check if it worked. So I read your response again and the thing that stopped it doing it was holding the power button down for 15 seconds. Now it doesn’t do it at all and I just press the button as normal. No idea what magic that is but thank you 🙂 

[Lil_Boy_Blue]

Prego.