half dead computer

[1969kappa]

It is a major problem as my desktop (500-374na) starts some times other times I press power on and it starts for a coule of seconds then shuts down other times I power on and the cpu fans goes super fast then the desktop shuts down I have played around with the umper on board after some faults and it works sometimes I dont know if it's a power issue bios problem operating system or CPU and do not know how to find fault I have a little know how nut nothing special and would like help on if it is knackered or not thank you to anyone who reads this or helps  

[WAWood]

@1969kappa

From your description, it sounds like the PC is not getting into Windows on any consistent basis but failing prior to that.

My guess, given that this PC model came out in 2014, is that your hard drive is failing -- as that will prevent the PC from completing the boot loader sequence and getting into Windows.

If your PC is new enough to support UEFI, you can use these steps to test the hard drive: http://support.hp.com/us-en/document/c00439024
 
If not, you have to follow these steps:
1) Press Esc key repeatedly, several times a second, while rebooting the laptop. Do NOT hold the key down, just press it over and over.
2) Eventually, you will see an HP Startup Menu -- that will look similar to the image below ...
 
3) press the Function key for testing the hard drive (usually F2) and let it run.
 
Please report back the test results.

[1969kappa]

It had crossed my mind it could be that but decided to ignor that I will try a new hard drive and installing windows and let you know thank you for your time reading and answering my question also thank you to all who read my post