I have a computer running Windows 7 (64-bit), with an Asus P8B75-M LX Plus Motherboard, Intel Pentium G860 @ 3.00GHz CPU.
Here's all the details of what I've done, but the short version is the original question.
This computer started having issues with random shutdowns about a week ago. They would usually happen 30-45 minutes after the computer was turned on, but sometimes it would take up to 6 hours to die. The VGA port also wasn't working and occasionally the Ethernet port will have lights on (flashing yellow left, solid orange right), but not connect to the internet. I was able to remote into the computer and see that windows loaded and programs could run. I checked the device manager and the only thing that showed under the Display Adapters was the LogMeIn driver.
After some trial and error I got the computer to load properly by unplugging the power cable and holding the power button for 30 seconds to try and clear any extra charge on the MB. Also leaving it unplugged overnight. Both of these options have worked, but not 100% of the time, sometimes I have to try it 4 or 5 times to get a proper start.
When I get a "proper start" the computer does have the Intel HD Graphic Driver in the Display Adapters section of the Device Manager and it doesn't have any issues with random shut downs. I can restart the computer as much as I want without any problems as well, but when I completely shut down the computer it will eventually revert to the "bad start"
- Replaced the PSU with a confirmed working PSU
- Tried a new SSD with a fresh install of windows and a cloned version of current SSD/Put the current SSD into another computer (worked fine)
- Reseated RAM/Tried confirmed working different RAM
- Applied new thermal paste to CPU/Ran a temp monitor on overnight/multipule times, CPU never got higher than 55°C
- Removing all peripheral devices
- Started in Safe Mode
- Updated Drivers
- New Sata Cables/Power cords
- Ran CPU/RAM/Chkdsk/sfc scans/tests
Eventually the "bad start" always comes back at some point when the power is completely shut off or when the power switch is used which leads me to believe there's an electrical issue in the MB itself. So coming back to the original question - Can bad capacitors on MB overload and cause boot sequence issues/random shutdowns?
I have removed the motherboard and checked for blown/warped capacitors or burnt connections of any kind, and I couldn't see anything wrong with any of it.