Computer shuts down

[Paul H]

My PC recently has occasionally (once every week to two weeks) completely shut down with no warning whatsoever, as if someone turned off the power switch or pulled the plug. There is no particular pattern I've noticed - software running, files open, etc, etc doesn't seem to make a difference.

It's a generic PC with a 3GHz Intel processor.

Any ideas what might be causing this?

Thanks,

[Kevin P]

The power just cuts off with no warning? Fans, lights, etc. go off? Either your power cord is loose or your power supply is dying. Is this a home-built PC or store-bought?

[Paul H]

Thanks Kevin. Yes, the power cuts off completely.

It's a store-bought PC, but not a brand-name machine with proprietary parts. I think the power cable is fine.

[Kevin P]

Is it still under warranty from the place you bought it from? If it is, they should fix it or provide the parts for you. If not, can you look and see what make/model of power supply is in the machine now?

[aud19]

Sure it couldn't also be bad RAM or hard drive sectors (as well as power/power supply issues)?

[Kevin P]

Bad RAM/hard drive can cause error messages, blue screens of death, bootup problems, but sudden power cut with no warning is almost always a power supply problem.

[peterS]

i had that on a mac... i dont recall what it was but it wasnt the power supply

[Azeke]

I agree with Kevin, I had the same issue with a Dell, replaced the RAM, harddrive, issues continued. Replacing the power supply is the most viable solution and probably the cheapest.

Peace and Blessings,

Azeke

[dyazdani]

I agree with Kevin on checking the PS first.

The only other thing I've seen on mine (but results in a reboot) is the CPU overheating. You may just check the CPU cooling fan just in case.

[aud19]

I've had some PC's at work reboot and/or shutdown with bad memory and HD sectors with nor error messages/blue screens. I agree the power supply could be it as well but if it isn't, those would be the next places to check IMO.

[David Meek]

My son's laptop had the same symptoms and it was caused by overheating issues from dust and such restricting the airflow to the CPU. A good cleaning (done once a month now) corrected the problem. A can of compressed air and a fine brush are even cheaper than a new power supply.

[Paul H]

Thanks all for the info and suggestions. The problem hasn't recurred in the past few days, so I guess I'll wait until it's truly broke before I fix it ..

[Club1820]

Well, it completely shutting down is definitely a sign that something is wrong. May not be smart to wait until it completely fails. Could do worse damage.

I had the same thing happen to me. Completely shutting down for no apparent reason. Turns out it was the power supply as others had mentioned. Specifically the fan in the power supply. I only realized this first by touching the back of the pc - it was extremely hot. Then I opened up the case and sure enough, the fan was not working and thus not cooling the power supply unit.

I replaced it with a new power supply I picked up off of ebay real cheap. about $25 for a new PS. Where retail they were going for anywhere from $75-$150.

Check the power supply quick. At least touch the back of the pc where the PS resides and see if it is hot.

Good Luck

[dirtfarmer]

that what happening to me right now reboot, when unload, reboot all time with out warning :M :M

but i found this info

i all most sure it my 250 watt PSU, but still waiting for my new 400 watt PSu to come from tigerdirect.ca via UPS,

ther sure charge enought for shipping, but soooooooooo slow, \pruchase 4 aug and to date 14, and still do not have it lol


How To Recognize And Repair Power Supply Problems

The Power Supply convert's your regular household current into low DC voltage used by the computer. When this component fails,there is simply no activity going on wih your computer.Remember to do the easy troubleshooting first.Inspect the Power Supply for any damage.Double-Check all connections.

Learning how to check your power supply and how to replace it when needed can be a life saver if you're a computer buff or in business with the trusted PC.Don't take for granted the simple pleasure of turning on your PC and everything works just fine.

We turned on one of our computers recently and in about one hour,it just re-booted itself.And it continued doing so about 10 times a day until we found out the power supply was the culprit.Things to look for when your power supply is going bad or just dies on you are the following.

NO POWER TO THE COMPUTER

Here you must first check the wall outlet for power by connecting another device such as a radio or lamp to be sure power is present.If the computer is connected through a surge protector,check it as well.

If the wall out has power,check the power cable going to the PC to see if AC voltage is making its way to the system unit.Do this with the use of a multimeter.

If there is power,you will have to open the PC and check for power from the power supply to the motherboard.

When using a multimeter to check voltage,be sure you have a good ground for the black lead of the multimeter.

RE-BOOTING PROBLEMS

One main problem you may face with an ailing Power Supply is that it may re-boot the computer without any warning.All information is lost and it seems as though this happens at the worst possible time.

Booting errors when the computer first start's up is another indicator of this component going on the blink.

POWER DISTRIBUTION PROBLEMS

When the power supply begins to fail,you may receive power at one device and not another.For example,the Hard Drive may receive power but the CDROM Drive has nothing at all.

Another headache with would cause re-booting is the intermittent power going to the drives or the motherboard itself.Follow the steps below to check your power supply should you experience some of the above problems.

CHECKING THE POWER SUPPLY

If the wall outlet,and the power cord are good,make sure the connection at the motherboard is secure.Then you may have to face the fact that the power supply itself is bad.If you have a Multimeter you can test the power supply output before purchasing a new one.Simply follow these steps.

Turn off the PC,but do not unplug it,open the system unit. Set the multimeter to read DC volts in the next range higher than 12 volts.Locate a power connector similair to the hard drive,or cdrom drive connector that is unused and turn on the PC.

You can also unplug a drive connector and use it as well.Turn on the PC and insert the BLACK probe into the power connector on one of the BLACK wires.Touch the RED probe to the YELLOW wire on the power connector.

The multimeter reading should be +12 volts Now touch the RED probe to the RED wire and the reading should be +5 volts.If no readings or different readings occured,you'll have to replace the power supply.If the readings were correct,you should check the P8 or P9 connectors at the motherboard. These connectors may also be named P4 and P5.To check these connectors,perform the following...

Insert the BLACK probe into P8 at one of the BLACK wires. Insert the RED probe into the P8 connector at the RED wire. The reading on the multimeter should be +5 volts

Check the power going to the Motherboard connections by inserting the RED probe into P8 at the YELLOW wire and you should get +12 volts.Leave the BLACK wire touching the black wire at the P8 connector.Check the BLUE wire and the reading should be a -12 volts.

Now move the BLACK probe to the BLACK wire on the P9 connector.Test the WHITE wire by inserting the RED probe and the reading should be -5 volts.Check the RED wires on the P9 connector and you should get +5 volts on each red wire.You won't get exactly 5 or 12 volts but the readings will be very close, such as 5.02 volts.

If the Power Supply is a couple of volts off,in either direction,such as when the RED wire should be reading -5 volts but it reads -8 volts,or if there are no readings,replace the power supply.

DO NOT remove the power supply from the system unit case when performing these tests.DO NOT perform these tests if you do not feel comfortable.Be sure to remove any and all electrical static build-up from your clothes and body BEFORE touching any parts inside the system unit.And NEVER open the power supply case for any reason,since high voltage may be present.

[Paul H]

My son's laptop had the same symptoms and it was caused by overheating issues from dust and such restricting the airflow to the CPU. A good cleaning (done once a month now) corrected the problem. A can of compressed air and a fine brush are even cheaper than a new power supply.

I vacuumed out the insides of the computer, and specifically some major dust buildup behind the fan that cools the CPU, and haven't had a problem in the last couple of days. Hopefully that was it, and nothing was hurt but my ego

Thanks,

[Paul H]

Wishful thinking on my part, to think that a good cleaning would fix all.

The computer will not start now. Power on, one quick flash on the keyboard lights, the fans run, but no signal whatsoever to the monitor, and the keyboard and mouse lights are not on.

This sound like a motherboard problem?

Thanks,

[Arneson]

I think everyone was correct to say your power supply unit was going out.
When the voltages to the motherboard are low and dirty your filter caps are hot and stressed. Look in to see if the large electrolytics are bulged or leaking.

[Paul H]

Wishful thinking on my part, to think that a good cleaning would fix all.

The computer will not start now. Power on, one quick flash on the keyboard lights, the fans run, but no signal whatsoever to the monitor, and the keyboard and mouse lights are not on.

This sound like a motherboard problem?

Thanks,

I installed the new power supply, and while the old one may have been faulty, I have the same situation described above.

Suggestions?

[Arneson]

The computer help forums are like the HTG in that if you post the make and model of
any board, the geeks (yes I said that), will tell you more than you want to know.

[Paul H]

Problem solved - as noted above I replaced the power supply. Then I replaced the motherboard/CPU, which was (also) fried. I'm guessing one of the several lightning storms we had here a few months ago may have caused the problems. (Yes I have surge protection).

[Arneson]

If you still have the old board, I wonder if you could look closely at it to see if the large electrolytic caps are bulged?
If so please offer the board up on ebay for refurb. I post with a group of guys that love to replace all the caps and save these parts from the land fill.

[Lex]

I didn't think this sounded like power supply. (late to the party)

Reboots can be heat related for sure. Everyone should vaccum out the internals of computers every so often, also recheck fan connections. I had a front fan accidentally unhooked caused me more grief than one can imagine.