Solved Dell optiplex 780 boot problem (does not always boot)

July 27, 2013 at 14:01:20
Specs: Windows 7
A month after the 3 year warranty expired, my Dell Optiplex 780 PC started to fail to reboot after 'Restart'. This happens on every 'Restart'. I wait for several hours and try to restart. In 3 times out of 10, it will reboot and let me continue with my Windows 7 software. The need for wait time implies that there is a cooling problem. I can't see where. All the fans work!
I thought it may be a BIOS problem. So I updated the BIOS from 0780-A03 to 0780-A14. Problem continues.
Dell diagnostics "ALL', i.e., hardware and software show no problems.
Since it does not always boot up, pressing F2, F8 and F12 on start up gets me nowhere. What else should I do?

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✔ Best Answer
July 28, 2013 at 06:54:57
Could be the power supply is failing (did you blow the dust out of it?) or could be an overheating issue. Did you remove the heatsink from the CPU to clean it? If you did, did you reapply fresh thermal paste & do it correctly? Have you checked the CPU temp either in the BIOS or by using hardware monitoring software? You can't rule out overheating if you have no idea what the temp is.

http://www.cpuid.com/softwares/hwmo...

http://www.dell.com/ee/business/p/o...



#1
July 27, 2013 at 14:23:30
A cooling problem would usually cause Windows instability and sudden shutdowns to protect the hardware from permanent damage, so If that's not happening I'm not convinced it's a cooling problem.

But in case I'm wrong, make sure the system case interior and all the vents are clear of dust and debris build-up. Get one of those PC air-blower cans purpose made for the job (Amazon is the best source for those) and give the interior a good blast around the vital components, including the vents.

Disconnect your PC from the power supply before doing that.


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#2
July 27, 2013 at 14:39:27
Include the fans and CPU heatsink in your cleaning.

Always pop back and let us know the outcome - thanks


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#3
July 27, 2013 at 17:54:11
Thanks, I have gone through all that (cleaning the vents, blowing off dust, etc., from inside the case and so on) repeatedly with no benefit.
You may well be right about the cooling issue. The need to let the PC alone by itself for a couple of hours (at least) puzzles me. That is why brought up the issue of cooling.
I have, again and again, disconnected and reconnected the cabling to the sub-systems. Again with no benefits.

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Related Solutions

#4
July 28, 2013 at 06:54:57
✔ Best Answer
Could be the power supply is failing (did you blow the dust out of it?) or could be an overheating issue. Did you remove the heatsink from the CPU to clean it? If you did, did you reapply fresh thermal paste & do it correctly? Have you checked the CPU temp either in the BIOS or by using hardware monitoring software? You can't rule out overheating if you have no idea what the temp is.

http://www.cpuid.com/softwares/hwmo...

http://www.dell.com/ee/business/p/o...


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#5
July 28, 2013 at 14:42:39
Thanks riider. Downloaded and checked core #0 and core #1 temperature. Temp rise to 55 C observed in core #0 . A more comprehensive program (OpenHardwareMonitor) also showed similar trends. Used Prime95 to stress the CPU. Yes, there could be a CPU heating problem. You all have been most helpful. But, my problem remains still!

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