Laptop powers down randomly

Ok, so I've looked at all of the other threads relating to power-down, but none of them seem to quite fit what's going on with me. This is kind of a unique story, so let me start from the beginning. Here are my specs:

HP Pavilion g7-2240us
Intel Core i3 @ 2.40 ghz
6 gb ram
Intel HD Graphics 3000

So my son stomped on this laptop. He told me he dreamed it was a monster that ate mommy so he killed it. Great. This killed the keyboard, the screen, and ripped the steel hinge bracket through the plastic case and demolished that corner. I rebuilt the hinge housing with epoxy putty, careful to not let any touch any components, replaced the screen, and the keyboard.

While I was waiting for the parts to show up, I ran the laptop through a second monitor after the case was fixed. That's when I started to notice that after roughly an hour of operation it shut down. It's done it when the system is completely idle with no one touching it, and when it's running a high-usage game, Star Wars: The Old Republic, with equal frequency.

This makes me believe that it's not a heat issue, (I cleaned it intensely when I rebuilt the case) and not a RAM issue, as it still does it when nothing is going on at all. I ran Device Manager, updated my drivers, ran UEFI diagnostics, and everything comes up clean. Still, it shuts down. Any ideas anyone?

 

Running Windows 8, too.

 

It is hard to tell if this problem is related to being stomped on - or just coincidental timing.

Unless powered off, there is always something going on. When you, the user, go idle, Windows and other programs become active with housekeeping, scanning, and updating chores.

I am not convinced this is not a heat issue because you say it does this after the computer has been running for awhile. While perhaps not one of the usual heat-sensitive suspects, it could be it takes that long for the entire system to warm up - perhaps then expanding a microfracture in the motherboard, a connection, a RAM module or some other component. You might try blasting a desk fan across it and see what happens after an hour.

Any errors shown in Event Viewer in the second or two before it shuts down?

If you have two or more RAM modules, try running with just one at a time. If only one, test your RAM with one of the following programs. Both require you to create and boot to a bootable floppy disk or CD to run the diagnostics. Allow the diagnostics to run for several passes or even overnight. You should have no reported errors.

Windows Memory Diagnostic - see the easy to follow instructions under Quick Start Information,
or
MemTest86+ (for more advanced users) - an excellent how-to guide is available here,
or
Windows 7 and Windows 8 users can use the built in Windows Memory Diagnostics Tool.​

Note, however, software based RAM diagnostic tools are good, but not conclusive.

 

In addition to Digerati's good advice, I would hold the fan exhaust port up to your ear while the PC is fully booted into Windows. Do this a few times over several minutes. If you do not hear the fan noise or don't feel hot air coming out, it could be a problem with the internal fan either not working or shutting down intermittently due to failing bearings.

Have seen this issue on a few HP i3 series notebooks in my shop over the past several months.

Hope this helps.