Usually within 15 minutes of startup, running Win 10, screen goes black then goes through the cold start routine then back to normal for another 5-15minutes. Replaced bios battery and tried a replacement power supply unit. Didn't help. Ideas, folks.

moby - 2021-09-25 16:07:00

Flakey hard drive. Get an SSD and clone it with AOEMIBackup and your problems will be gone. Plus you'll end up with a faster HD.

tegretol - 2021-09-25 16:09:00

as much as a SSD is a good investment, there are plenty of other things that can cause random reboots you should probably check out first...

I would start with
Unplugging any/all USB peripherals
Safe Mode... boot into safe mode (and then safemode with NW) and see if it does the same
Event Viewer... Inspect the system log for the bugcheck event to get the stopcode
WhoCrashed... Download and install, let it analyse the crash dumps - often it can point to a driver or device that is causing the problem

if windows isn't leaving a crash dump then it might be hardware instead of software/drivers.

It would be a rare occurrence for a bad hard drive to cause a physical reboot, usually they just stop or go slow as. A machine I had last week doing the same was traced to a USB wifi adapter.

Good luck these ones are really a process of elimination

Edited by king1 at 4:35 pm, Sat 25 Sep

king1 - 2021-09-25 16:24:00

tegretol wrote:

Flakey hard drive. Get an SSD and clone it with AOEMIBackup and your problems will be gone. Plus you'll end up with a faster HD.

Oh really ? If you're that psychic do you have tonight's lotto numbers handy please ?

You have no idea what kind of hard drive they have - indeed they may already have an SSD. And irrespective of that without a diagnostic run on whatever it is unless you are a hard drive sales person there's little reason to suggest that replacing it might be of help

Actually - OP - BEFORE you go spending money on a new hard drive which may not be necessary and quite possibly is not the cause of the shutdowns you might like to investigate one or more of the many things potentially causing this problem. Could be bad capacitors on the motherboard, could be overheating for one or more reasons, could be a dying hard drive.

Also check event viewer for hints. Check running in safe mode to see if that reduces or removes the problem.

Edited by nice_lady at 4:48 pm, Sat 25 Sep

nice_lady - 2021-09-25 16:34:00

Run a memory check:
Control Panel > System and Security > Administrative Tools > Windows Memory Diagnostic.

Takes a little while.

tmenz - 2021-09-25 22:14:00

read the event logs, theres no point to randomly swapping hardware.
Run some temp software (ie coretemp ) to make sure its not overheating.
Run the dell diagnostic utils.

bitsnpieces2020 - 2021-09-25 22:51:00

https://community.spiceworks.com/topic/448138-dell-optiplex-
780s-reboot-sporadically-all-by-theirselves

tegretol - 2021-09-25 23:18:00

moby wrote:

Usually within 15 minutes of startup, Replaced bios battery and tried a replacement power supply unit. .

Why?
Diagnose it first. batteries don't restart PCs, they just put the date back to manufacturing date...

Mines 11 yrs old and still good.
See why,
1. Click the Search button, search for and open View advanced system settings.

2. Click Settings in the Startup and Recovery section.

3. Remove the check mark next to Automatically restart, and then click OK.

4. Restart the computer.
Now it should give an error instead of the reboot loop.

lythande1 - 2021-09-26 09:10:00

moby wrote:

Usually within 15 minutes of startup, running Win 10, screen goes black then goes through the cold start routine then back to normal for another 5-15minutes. Replaced bios battery and tried a replacement power supply unit. Didn't help. Ideas, folks.

Sorry, a little confused about this model
I thought they were a core2duo with normally an E6600 to E8400 cpu.
The odd one with a Q series cpu

mrfxit - 2021-09-26 09:53:00