Dell Latitude E6410 powering off

[madder]

Dell Latitude E6410. Intel i5 Processor. 8GB RAM. Windows 7 Ultimate.

Recently dropped the laptop. Hard drive then failed.

Replaced the Hard drive and reinstalled Windows 7 Ultimate. Now the Laptop refuses to run windows update.I soldiered on anyway as it was working fine.

Worked fine for about a month or 6 weeks, but then started turning itself off. No blue screen, just a loss of power. Normally it would stay on for 30 minutes or an hour before this would happen. It did feel quite hot too I must say.

Here are the things I have tried so far:

Thermal Paste. Opened it up and had a look at the paste on the processor and GDU. Looked old and dry and was spread out around the processor onto the PCD board. So I cleaned all the old paste off, and I applied new Thermal Paste. I made sure to put enough paste on.

Then when I started the computer, it powered off much sooner. However, it didn’t feel hot at all this time.

If I leave the laptop for a few hours and start it, then it stays on for about 1 hour maximum and then knocks off again.

BIOS. I then tried a BIOS update and I am now running the latest version. Nothing changed.

RAM. Next thing I tried was to swap out the RAM sticks and see if any of them could keep the laptop on when running in the machine alone. Neither did. But one lasted far longer than the other. One lasted an hour. The second lasted 2 seconds. The next thing I did was tried the RAM(the better one) in the RAM slot that was vacant during the previous test. Lasted about 30 minutes and knocked off.

Could the two RAM sticks be bad? I suppose they could but how likely is that? I intend on buying a new CMOS battery and try that too, but it keeps the right date and time and so that too is unlikely? Any ideas?
It won't stay on long enough to get through a diagnostic test. Thanks.

 

[madder]

UPDATE:
I tried a new RAM stick and the laptop still powered off after about 25 minutes. I tried a new Power supply and even a new battery and still nothing solves the problem? I even tried running the diagnostic test, and it always powers off around 2 minutes into the CPU test, after passingthe initial tests on video, LCD etc. I haven't swapped out the CMOS battery yet, but since the computer still holds good date and time, I doubt that it's a CMOS problem. SO what does that leave me with? Is there any chance that it could be software? Or is this likely a motherboard issue?

 

[Monkeh]

It could be a thermal issue, either overheating a component or a bond wire or solder joint being cracked by the fall and coming apart as it heats. The issues with the RAM may suggest the slots have suffered cracked joints (there's some leverage there). These would be hard to pin down and fix without a microscope and some soldering skill.

 

[madder]

Thanks Monkeh. I did change the thermal paste, and the problem persisted but the laptop was most certainly running cooler. I took the bottom casing off the laptop and scrubbed it with a toothbrush and cleaned out any trace of dust. It has been running fine ever since the cleanout.