Power on issue after cleaning and video card upgrade.

[Donald0Duck]

I have a HP ENVY Phoenix 810 that I use as a spare computer. The GPU has been dying for a few years now but it generally worked unless I gave it load and then it would start to overheat. Cleaning out the fan a few times has prolonged its life but sometimes it still makes really bad noises. The other day I gave it (and the processor) some new thermal paste and then I closed it back up. From that point on, all it does it turn on but not boot. When you hold down the power button, it doesn't power off - you need to unplug it to turn it off. 

At first I thought I had finally killed the video card. It's main wire is badly kinked near where it meets the board and it's exposed. I may have been too rough with it trying to clean it out and seeing how far I could break it down. I decided to try a different one, Nvidia GT 1030. The same problem occurred. 

I have even tried connecting with DVI cable directly to the motherboard without a GPU and the same problem occurs. 

I think I may have forgotten to plug something from the power supply back in (I took stuff out to get it out of my way) but I can't think of what. Everything is in the right position that I can see and only the extra ends in the bundle are unplugged. 

Is there a complete list of power supply connections that need to be made somewhere? 

[erico]

How about identifying your PC beyond HP ENVY Phoenix 810. That is a series of desktop PCs.

No. There is no list of power connections.

How about taking a digital photo of the motherboard so we can see what you did connect.

Show any cables with connectors that are not plugged in as well

You own a mobile phone and did not take photos.

Always do that before taking something apart if you are not sure how things go back together.

[Donald0Duck]

My apologies for not giving enough information! My PC is a HP ENVY Phoenix 810-160 and the serial number brought me to this page: https://support.hp.com/us-en/product/hp-envy-phoenix-810-100-desktop-pc-series/5399342/model/6529902... . I am accessing this board on a different PC so using any of the auto detection tools here isn't going to help. 

Here are some pictures of my current connections and the unused connections from the power supply: 

[erico]

Thanks. That does help.

I see the CPU  power connector and the Mainboard power connected as required.

Your video card may have "passed the bar".

It would appear to be time to source a newish, perhaps eBay or flea market sourced,  low power video card.
I wouldn't put very much resources into an eight year old PC, but that is just me. 🙂

When the BIOS does not have a satisfactory video check, nothing works as expected. 

You may find this video interesting.

[Donald0Duck]

Interesting video - Unfortunately I cannot get the video to display even if I connect it directly to the motherboard. I tried powering on with the original video card back in as well and the same thing happened. I will continue to try different configurations and different ways to maybe get to the BIOS in hopes that it will get the display to come on. So far everything I do causes the same behavior of the PC: Power goes on but no display or response to any input - even holding the power button doesn't power it back off, it needs to be unplugged to power off. 

[erico]

Generally, holding the power button for four seconds, is termed a hard reset and should shut down a Windows PC or laptop.

I would try another video card and also reseat the memory modules.

That is what my experience troubleshooting PC tells me.