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Failing PSU


OSNN Veteran Original
For the last couple of weeks my computer has been rebooting by itself for no reason. It would do this when I am asleep, I would wake up and notice nothing is open, clearly was rebooted.

It recently started to do it more often, when I get home from work, it was in the process of rebooting. Now I tested for virus and spyware and all that, my system is clean. I keep care lol Tried to think if any new programs or old ones could do this, no. No system updates were being installed, and I have it set to not do it without me. So not that.

I can't think of anything else, except for a PSU that might be dieing on me. Well that is the only think that makes sense to me. I am assuming it could be a motherboard problem or something like that. It's been awhile since I have had any real issues.

What do you think? If it is the PSU, anyway to test it to know 100% before buying a new one, don't really have money for that right now.



F@H - Is it in you?
Staff member
Political User
It seems it is the PSU.

Try stressing out the system by running some benchmarks/stressful games so that you can "trip" the system.
Sadly, it could be anything in the system. My own worst reboot nightmare was a sound card it took me 6 months to isolate, and then it was by accident when I did a sound card upgrade and the reboots stopped.

First make sure it's not the house power. If you have touch lamps, are any turning on by themselves over night? Another way is digital clocks resetting. If you have a digital alarm clock take out the 9V battery back up and see if the clock or alarm resets over night. Most equipmnt has some amount of hold up time so short spikes may not affect many items but will affect a PC.

Once the input power is verified good start pulling unecessary add ins out of the PC. This will also reduce load on the power supply.

I have never seen a power supply that "dropped out" over night. Usually they won't start up or you will have a problem under heavy load like gaming. Also the load should be low over night (unless you are folding, etc.)

Any chance one of the energy star functions is kicking in, though that should not close aplicaitons by restarting the system? Check the windows fault log and see if it is reporting anything like memory failures, etc.

Make sure you do not have the system set to REBOOT on Fault. It will prevent you from seeing the cracsh window and will look like a power loss.


The Analog Kid
Yeah, definitely make sure it isn't set to reboot on error and see if you get a blue screen error message. Also, is the unit on a UPS? Is the UPS in good shape?


OSNN Veteran Original
Where do I find the reboot on fault options, it's been awhile.

Second, my first thought was the house power. I am now living on my own in a small place, where I know the wiring is old and I was cautioned to using to much power. Though at night, nothing is running, a mini-fridge, water cooler, microwave are plugged in, but I assume they don't use much. Even if they did use alot of power, I have had all that, all the lights on, my TV on, 3 consoles on, etc without issues. Even with that thought, everything in my place do not have times on it, or anything I could tell if it was reset (i never set the clock on my microwave lol).

And then I was thinking if the power in the place cuts out, my computer wouldn't reboot right? It would just be off, the computer cuts out, then turns back on. Which is weird in the first place.

Also, no UPS.

Now I have been having video driver issues the past couple months, well I think I have been. When watching videos, HD or regular, the screen would turn a full color (related to what was being watched), freeze, then crash back to desktop, with a popup in the corner saying my video drivers have crashed. I have since updated them twice, and still happens once in awhile. I don't think that could cause reboots, even if it could, that was happening way before this problem started.

And when my computer gets back to the desktop after rebooting, its normal, no messages or anything to tell me something went wrong.


The Analog Kid
1) What OS are you running?

2) Knowing that the power in your new place is admittedly "wonky," I'd highly suggest investing in a UPS. It will help with power fluctuations and 'some' line noise.

American Zombie

Staff member
Political User
And when my computer gets back to the desktop after rebooting, its normal, no messages or anything to tell me something went wrong.
Nothing in event viewer?

Windows 7 logs just about everything but it may be in a different place other than the application, security, system logs.

Windows 7 also has logs for every Microsoft service/application.


OSNN Veteran Original
Yea, forgot about the event viewer. Just looked at it.

There are a bunch of stuff in there, a couple that are Critical, and are named (source) Kernel-Power.

Those all seem to happen around the times I think the computer rebooted, or when I know the computer rebooted. What does that mean? Kernal-Power?


OSNN Veteran Original
There is quite a bit of info there. Not sure what is what.

I did change the setting in the system to not automatically reboot on failure.
This only applies if you are sure there is a power problem. UPS will not help if you have flaky hardware (or drivers) in the PC.

How big a UPS you need depends on how much power your system draws and how long it needs to fill in. After that it gets really complicated...

There are two types of "UPS" there is the true UPS which runs all the time providing filtered, regulated, power from the line and during drop outs feeds from the battery. Then there is the Backup UPS that idles most of the time and only provides power during a line drop out. Advantages/ Disadvantages:
UPS - cost is higher, may die sooner, uses more electricity (10-20% more). Provides better, safer power to the PC.

Backup - may not take over fast enough to stop a brown out (depends on how good a PSU is in the PC. The PC PSU has to survive long enough for the Backup to take over.) May or may/not provide filtering and surge protection (most do, check the spec's). The last time I looked good PC PSU are now listing hold up time numbers so you can see if a given Backup is fast enough to work with your PC PSU.

Sizing - You do not need to plug your printer or monitor into the UPS. PC for sure, router and modem possibly if you are having problems during the day or with long downloads crashing. Ideally you should size the UPS 20% larger than the Watts rating of your PSU + anything else you need to backup. BUT, if you have a mega size PSU (750-850W) and are only using half it's capacity (550W system) ,and have no major upgrade plans, you do not need the over kill and can save some money.

Fill-in Time - (biggest cost driver is the battery) since you are just trying to survive a surge or spike a few minutes of battery life is all you need so you can save money.

Battery shelf life
Battery maintenance
Battery replacement cost
Keeping a UPS cool since it runs all the time
Buying a quality unit that will not fail and take the PC with it
Is the PC PSU good enough to fill-in until the Backup UPS kicks in
If it is just a short power spike why isn't the PC PSU taking care of it? Is anything else acting up like touch lites turning on over night, clocks resetting, etc.?


OSNN Veteran Original
That setting I changed for it not reboot on issue, well now I wake up in the morning to a grey screen. The monitor is still on, but I can't do anything. Clicking and moving the mouse and keyboard do nothing, turning it back on and off do nothing. I have to hit the reboot button on my case.

So what ever the issue is needs to reboot the system.
Needing a hard reset in the morning does not sound like a power supply issue. If the power browns out it usually causes a reset not a lock up

I'd look elsewhere than power for the cause.


OSNN Veteran Original
What else hardware wise can cause something like this?

I have needed a new system for awhile now, but don't have the money. Explorer crashes quite often for ever now, over many reinstalls and formats. I have spent hours and months researching why, but have solved nothing. Maybe this issue has been come worse.

Though what kind of software problem continues after a format? lol


OSNN Veteran Original
In my research of my crashing Explorer, and maybe this being related. The 2 things that seemed logical were a failing harddrive, and my custom uxtheme.dll.

Now I replaced the uxtheme.dll and used another way to change themes, but never on a fresh install. And well I have used many different applications that test hard drives, some say there are issues, and some say they are fine.

Is there any way to 100% test a hard drive and know if its dieing?

And its about time for a format, so that might be what I will do soon.
The built in SMART test is generally very good at catching unreliable HDs. Check your drive's website for utilities to stress test the drive. WD has a very good test suite which even generates an RMA form if you find an issue, Seagate has some but I'm a WD fanboi and not that familiar with Sagate.

Any hardware in the system can be the issue the crash files generally help ID the HW but if all you're getting is "power fail" messages there is no help there.

If there is a software issue reformatting is no guarantee of a fix, You will automatically reload all of the same drivers and operating system files. I found this out with a slow boot issue. I'd reformat and over a couple days get all the updates and software reloaded. Boots would be nice and fast up to loading the updates for the last few months then boot time would suddenly double.

IE has become unreliable since about August. I'm having crashes and hangs at home and at work. It got so bad I use Firefox and Opera about 99% of the time now.

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