New dv7 motherboard boots up but soon closes down everything without warning

[joehelf]

I recently had the blank screen with blinking caps lock and num lock buttons. So I bought a new motherboard on ebay. It was advertised as a dv7 1200 series motherboard. The seller said these motherboards were built about 10 years ago and never installed. It looked identical to my old one. I installed it and the computer booted up to Windows Vista with the users all appearing on screen. I've booted up using F2 key and tested memory, all 100% okay. Tried testing hard drives but computer won't stay on long enough to test these completely.

My problem is the computer boots up and the whole computer just suddenly shuts down. No warnings, no beeps, no sounds. I think it is trying to launch something that is stopping it. I've tried booting in safe mode and it still does the same thing. I've even set a stop watch to track its time on. It seems to stay on for about 2 mins 50 secs and then shuts off. Is there a way to stop any resident programs that may be trying to start if this is what is causing the conflict? 

Thanks and blessings in advance.

[WAWood]

@joehelf 

Sorry to say this, but often, when folks buy HP motherboards online, since these are ALWAYS from used equipment, they very often do not work well, or even at all.

We have nothing you can run in terms of diagnostics to check out the board and we are not HP Tech Support, so we have no way to walk you through any troubleshooting of it.

If it is not working properly, the only real option you have it so return it for a refund.

[joehelf]

Well I don't know if sending it back or not is the answer. I think it is something to do with heat. I took the laptop outside today since the temperature was in the high 30s and I let it sit there for about an hour. I then went out and turned the laptop on and it ran for at least 15 mins. I was able to get into the operating system and was able to navigate and just about anything. Then I shut it down and took it inside. Once inside I turned it back on and loaded windows and was navigating around when suddenly without warning it shut off just like before. 

So now my question would be what part of a laptop would cause it to shut down because of some sort of heat problem? The cooling fan and heat sink both seem to be working fine. But definitely there is something heat related on this system that it doesn't like. 

Any ideas?

[WAWood]

@joehelf 

The four things in the laptop that generate heat are: disk drive, system memory, CPU, graphics processor.

I have no idea why a replacement motherboard should operate at any temperature different than the original -- so that alone should not be generating more heat.

You can put your hand on the underside of the case while it is running, over time, and see what parts become the hottest -- that will give you some idea what part is generating the most heat.

If you've checked the fan and it's working and the vents are clear, I don't know what else to suggest.

[joehelf]

I think part of my problem is I'm dumb. I have very little knowledge of all the inners on one of these motherboards. I bought the motherboard because the pic looked almost identical to the one I have with the graphics chip that was showing signs of going bad. The one I bought was advertised as a dv7-1200 series motherboard and my laptop is a dv7-1157cl. I thought it was close enough. There is a difference in the two but not bad. The new board has what appears to be a different video chip that would require a different heatsink type. In the manual it shows 3 possible different heatsinks. They are numbered 480472-001, 480473-001, and 481144-001. The problem is the manual doesn't designate which heatsink is which. Does anyone out there know the difference? One has just a curved pipe. One has a curved pipe in the form of a question mark and one has two pipes for different chips. Here is a link to the manual I'm looking at. Look at page 116 and 117. I'm looking for the heat sink that has 2 pipes. https://www.manualslib.com/manual/273613/Hp-Pavilion-Dv7-1023.html?page=116#manual