System Automatically Reboots

[raptorz]

My system reboots on its own every few hours. Its driving me crazy. I am not able to figure out what exactly the problem is. Hope you guys can help me out.

Here are a couple of observation i have made.
1. Reboots are random. It happens once every 6-9 hours. Its not frequent.
2. I have reinstalled vista. I still have the problem. This should rule out any software related issue. (No virus, spyware, other conflicts)
3. The temperatures are normal. There is no overheating in any component.
4. I ran a stability stress test(using everest) for 2 hours, the system did not reboot. The reboots are totally random.
5. The voltages from smps(Powersafe 400W) seem to be fine.
6. Very rarely, i have this issue where my system refuses to switch on. My motherboard(Intel 945GNT) produces 3 beeps. It boots fine if i disconnect the power, leave it for a few minutes, and connect it back.
7. I am using APC UPS. I dont think there is anything wrong with it..
8. One more important thing. There is no error message, or blue screen of death. Just plain reboots.

I think this has to be a hardware related issue. Its got to be either the power supply or the motherboard.
My config in brief: Pentium D805 + Intel D945GNT + Geforce 9500GT + PowerSafe 400W + 2GB 667 MHz Transcend RAM + Sony DVD Writer.

Please leave a reply if you have any suggestions..

[Raccoon]

I'v had similar issues twice. Both times, after wasting much time in checking out other things, I found that the culprit was the RAM! You have cast your suspicions on most other things, but have left the RAM out! Try out other RAM... or if you have more than one DIMMs, use your comp with only 1 for a time and see (however, both your sticks may have become bad, for a variety of reasons.. so try with new RAM eventually, if you cant isolate the problem).

[infra_red_dude]

Probable culprits:

1) RAM
2) Bad CPU or cache
3) Loose power connectors (from the SMPS to the peripherals or the main power cord)
4) Bad sectors on the hard disk (if some system file resides in that sector)

[ultimategpu]

yesterday i got this problem , i changed the thermal paste , and did better cooling , now its not at all rebooting ,,,,,,,

Originally Posted by Raccoon

I'v had similar issues twice. Both times, after wasting much time in checking out other things, I found that the culprit was the RAM! You have cast your suspicions on most other things, but have left the RAM out! Try out other RAM... or if you have more than one DIMMs, use your comp with only 1 for a time and see (however, both your sticks may have become bad, for a variety of reasons.. so try with new RAM eventually, if you cant isolate the problem).

buddy if RAM is failure it will show it "blue screen of death " not rebooting

[infra_red_dude]

^^^

1) He said the temperatures are OK.

2) Not necessary that for bad RAM it must always show BSoD. In fact, it may be showing that he may haf enabled reboot.

[dheeraj_kumar]

@raptorz

Press windows key+pause/break. Advanced tab. Startup & Recovery Settings. Untick "Automatically Restart"

And I go with Infra Red Dude's culprits list, but there couldnt be system files in bad sectors, as windows wouldnt have been loaded in the first place.

[infra_red_dude]

^^^ Aah, thats a valid point! Mebbe the system files are not there but a specific file being written to resides there, or maybe a part of the swap file? Difficult to judge but Bad sectors surely be a culprit.

[ultimategpu]

Originally Posted by infra_red_dude

^^^ Aah, thats a valid point! Mebbe the system files are not there but a specific file being written to resides there, or maybe a part of the swap file? Difficult to judge but Bad sectors surely be a culprit.

bad sectors in the hard disk does not reboots !!!1

[infra_red_dude]

^^^ And what makes you think it doesn't?

[raptorz]

Thanks guys for the replies.

@Raccoon
Did you get bsod's while you had problems?

@infra_red_dude
I am going to test the RAM today and report back. I have already disabled auto reboot in case of a bsod. There is no bsod. I dont think my hdd has gone bad. Let see if nothing works, i will check that too.

@ultimategpu
I agree with you. Whenever i have come across ram related issues, i have always seen bsod's. Anyways i will the test the RAM today.

[Raccoon]

@Raccoon
Did you get bsod's while you had problems?

No BSODs for me. In fact thats what made the problem so hard to pin down! My comp used to hang at the mobo splash screen when booting up. But whenever I kept it on for say a minute and then rebooted, it would booth normally. But after that, an infrequent randoom reboot used to occur. I even tested the RAM using MS Mem Diag... but it did not find a single error! Obviously, its test methods could not find the problem. After wasting lot of time, finally got a new 1 GB Dynet DDR DIMM and the problems vanished!

Had a memory problem about 3 years ago too... just random and frequent reboots... but at that time MS Mem Diag correctly reported errors, so didn't waste much time.

Unchecking "Automatically Restart" did not help me at all, when I had the above problems.

[rhitwick]

Originally Posted by Raccoon

No BSODs for me. In fact thats what made the problem so hard to pin down! My comp used to hang at the mobo splash screen when booting up. But whenever I kept it on for say a minute and then rebooted, it would booth normally. But after that, an infrequent randoom reboot used to occur. I even tested the RAM using MS Mem Diag... but it did not find a single error! Obviously, its test methods could not find the problem. After wasting lot of time, finally got a new 1 GB Dynet DDR DIMM and the problems vanished!

Had a memory problem about 3 years ago too... just random and frequent reboots... but at that time MS Mem Diag correctly reported errors, so didn't waste much time.

Unchecking "Automatically Restart" did not help me at all, when I had the above problems.

Same happened with me too, frequent restarts, freezing at start up, if left for a few minutes system would start and no BSoDs.
Couldn't find any clue. As I thought I'm the best(), didn't even contacted with vendor for 2 months and d nightmare continued.
Then I gave up, went to vendor and they changed the RAM and all was allright.

AND @thread starter: thats a pretty good problem description. Thanx.

[raptorz]

@Raccoon, @rhitwick
Thanks for your replies. Now I strongly feel that RAM is the culprit.

I have got 2 GB RAM(1GB + 2 x 512MB). I used the system today with the 1 GB module only. I still have the issue. I ran Windows Memory Diagnostics and memtest86+. No errors.

Now, I am using the 512 MB modules. Let me see if it restarts again.

[Raccoon]

Another component I had a HUGE problem with, and which gave me frequent reboots was my UPS. But then that was a Powercom UPS - one of the most abominable things ever made by man (have written about it in the Hardware to Avoid thread)! Since you have APC, and it is immeasurably better than Powercom, I doubt its the cause of your problem, but still worth checking out, if you cant find any other cause.

[defredey]

Primarily all the major concerning areas leading to this problem has been commented here as I see. Just to add to your knowledge an incident of mine which also led to reboots at periodic interventions. In my case the RAM was not the culprit though, it was dust accumulated in the heat sink of the processor fan that caused the problems.
What was even surprising the CPU temperature did not show me any abnormalities which foxed me initially. Maybe this is not the case for you but shared for all the others who may be helped trying this out too. I need to know about konica minolta printers though.

[raptorz]

@Raccoon
I used my system without the UPS today. I still had the problem. The UPS is fine.

@defredey
My fans are not very dusty. I will clean the the system.

RAM - No errors with Windows Memory Diagnostics and memtest86+. I used 1 GB and 2 x 512 MB separately for a few hours. It still reboots.

I unplugged every single connection, removed processor, and cleaned everything. And it still reboots...

[adi007]

A lame suggestion : use XP or linux and try whether the system reboots automatically or not

[Raccoon]

As I said earlier, its possible all ur DIMMs are faulty (can happen due to various reasons). Suggest you get stick from somewhere and try... esp. since you have already ruled out most other things.

[raptorz]

@adi007
I used xp. It still reboots.

@Raccoon
I dont think all DIMMS can be faulty.

Is there any way to test the smps?

[sakumar79]

It is also possible that your RAM slots are faulty instead of your RAM... I had this problem with my current computer and it caused quite a headache before I could figure it out... Try a single RAM module and test it on each slot available to verify if one or two slot is faulty...

Arun

[NucleusKore]

The last time I had this problem I had to change my hard disk. These sudden reboots could be caused by just about anything.

Is S.M.A.R.T. enabled in your bios?

And if I may suggest, please check your hard disk with these tools
http://www.ultimatebootcd.com/

[raptorz]

@infra_red_dude, @NucleusKore
I have got two hard disks. One having xp and other having vista. I got reboots with both. I have set optimal defaults in bios. I dont think the hard disk is the cause.

@sakumar79
Oh.. I didnt know that.. Let me try.

Regarding smps, i disconnected all power connectors except the hard disk and mobo. I got 6 reboots in the last hour.

[imgame2]

if all the things suggested by forum member fails ..i think its ..the problem with ur PSU ...try changing ur PSU and see what happens ...

[NucleusKore]

Originally Posted by raptorz

I dont think the hard disk is the cause

Better to verify and exclude than think

[Raccoon]

Originally Posted by raptorz

@adi007
I used xp. It still reboots.

@Raccoon
I dont think all DIMMS can be faulty.

It is not impossible dude... and I speak from experience!

And as suggested above... suspect the RAM slots after that...

[iinfi]

i m not a h/w freak but still there are 3 things which i feel r possible.

1) i highly suspect ur smps is faulty which mite b giv voltage fluctuations.

2) outdated/corrupt display drivers. (i v faced this problem on my PC b4) use linux and boot to the command prompt n chk.
i suspect this even if you say u v tried with both xp n vista

3) have ur motherboard checked with your vendor (not jus RAM slots).

[raptorz]

I found this interesting article on wikipedia today:
http://en.wikipedia.org/wiki/Capacitor_plague

As the capacitor ages, its capacitance decreases while its equivalent series resistance (ESR) increases. When this happens, the capacitors no longer adequately serve their purpose of filtering the direct current voltages on the motherboard, and system instability results. Some common symptoms are:

• Not turning on all the time; having to hit reset or try turning the computer on again
• Instabilities (hangs, BSODs, kernel panics, etc.), especially when symptoms get progressively more frequent over time
• CPU core voltage or other system voltages fluctuating or going out of range, possibly with an increase in CPU temperature as the core voltage rises
• Memory errors, especially ones that get more frequent with time
• Spontaneous reboots
• In case of on-board video cards, unstable image in some video modes
• Failing to complete the POST, or rebooting before it is completed
• Never starting the POST; fans spin but the system appears dead

Unlike the physical signs which are conclusive evidence the capacitors are failing, many of the operational signs may be caused by other factors, such as a failing power supply, dust clogging a fan, bad RAM, or other hardware problems. Instability, once the operating system has loaded, may indicate a software problem (such as some types of malware, poorly-written device drivers or software), and not a hardware problem at all. If any of these symptoms are experienced, removing the system's case and inspecting the capacitors, especially those around the CPU, may immediately identify capacitors as the cause. If there are no physical signs, an oscilloscope may be used to examine the voltage on the capacitors, with excessive ripple voltage being a sign the capacitors are not doing their job.

The capacitors in my powersafe smps almost look similar to the ones in the picture. Two capacitors have got a bulge at the top.



I will try with a different smps. Hope it will solve this problem.

[infra_red_dude]

Bulge.. Hmm.. looks like a cap. leak or a cap. about to leak. They can be replaced and set right. Take it to the local electronics guy. He'll fix it.

[raptorz]

Problem Solved. My Powersafe SMPS was the culprit.

Thanks for all the help.

[skippednote]

Almost all the restart problems are related to a bad smps