After windows 10 update my computer shut down. When I rebooted I had no signal to the monitor.

[NJBravo]

I purchased a used cpu / did not work. Video card / did not work. Swapped my memory sticks around. / did not work. BIOS reset / did not work. I did notice that when I hit the power button it shuts down immediately. I used to have to hold it down for a while before it shut down. Also noticed about 4 whines from the power supply on startup then goes away, fan is spinning. I never noticed that before. Microsoft swears it was not the update! I know people who are having the same problem after the update.
Please help. Thank you!

[Elohi_NR]

Hi @NJBravo,

Welcome to the HP Support Community. 

I'd be happy to help you! 

Excellent description and a great diagnosis. It is greatly appreciated.           

This could be a hardware issue or the OS might have corrupted. 

What OS, did this PC come with?
 

Some PCs may not be compatible with other OS versions. However, let's try these steps. 

POWER DRAIN:

Please disconnect all the devices and cables connected to your computer including the power cable and then press and hold the power button for about 20 seconds and connect the power cable back again and try to power on the computer.

CBR:

Press windows key and then followed by the key "B" this time and then the power button for around 3-4 seconds, then release the power button and continue to hold windows+B for 3-4 seconds more.

CMOS RESET:

Press windows key and then followed by the key "V" and then the power button for around 3-4 seconds, then release the power button and continue to hold windows+V for 3-4 seconds, you may not receive a response from the computer, Please let me know what happens.

Check with different Monitors to isolate the issue, to see if its the monitor or the PC itself has a hardware issue. 

Hope this helps! Keep me posted for further assistance.

 Please mark this post as “Accepted Solution” if the issue is resolved and if you feel this reply was helpful click “Yes”.