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Home built PC rebooting suddenly!

ytowndj
ytowndj asked
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Last Modified: 2010-04-25
Hi... I recently built a new PC for my father, a Pentium D machine using all brand-new parts from Tiger Direct. The machine occasionally reboots at random, but I've really noticed the problem more when running a virus scan or a disk cleanup. When the problem first occurred, I did notice a slight grinding noise coming from the CPU fan, so I replaced that on warranty, and I haven't heard the noise yet. CPU temp is normal, roughly 38-40C idle... There's really no extended heavy CPU use, as my parents don't do any gaming, just MS Office, Quicken, web & email... My gut reaction is a power issue, because I'm running the Pentium D 830 with 1GB DDR5400, (1) Seagate 250GB PATA HD, (1) Hitachi 20GB EIDE HD, (1) ATAPI DVD+/-RW, (1) ATAPI DVD-ROM, (2) 120mm ball bearing case fans, 1 input on back of case, 1 output on side panel, almost directly above cpu fan. The PSU currently in the machine is only 400W. I'm considering upgrading it to a 600W, but I'd really rather not unless the chance of it correcting the problem is high enough. I've already tried disconnecting 1 HD and 1 DVD-ROM, and still ran into the problem. Any advice would be greatly appreciated.
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Commented:
It might be the power supply, but run Speed Fan first, set it to show in the Taskbar, and see what the temps are when it reboots.

SpeedFan.  
http://www.almico.com/speedfan426.exe
Quid, Me Anxius Sum?  Illegitimi non carborundum.
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Commented:
i would check first the power needed :
http://extreme.outervision.com/psucalculator.jsp      
then set the pc NOT to reboot on errors : in device manager, advanced tab, restart settings. then you'll have the BSOD with an error code, that can give more info.
Alternatively, you can also test run with the minimum connected (only 1 disk, no cd  drive, no add on cards)
Chris BRetired

Commented:
<<1 output on side panel, almost directly above cpu fan>> Turn it around - it is running opposite to the CPU fan therefore preventing proper airflow. Turn the rear around also so airflow is out.

Chris B
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Commented:
Check out the boards Caps.
www.badcaps.net

cf101

Author

Commented:
First of all, I appreciate all the ideas, so far. I'll be heading over to his house again tonight to do some more diagnostics. I've already downloaded the ultimate boot CD, and I'm going to test the drives and memory tonight, and I'll probably go ahead and order a 600W PSU...
I guess there is not much chances of a bad caps because everything is brand new.
It might most probably be the power supply being unstable.
Go get power supply from reputable brands like Antec etc etc...
Gary CaseRetired
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Commented:
Power is certainly a strong possibility here ... a virus scan is a fairly CPU-intensive operation which significantly increases the power draw of the CPU while at the same time doing a lot of activity on the hard drives.   But a high quality 400w supply SHOULD be enough for this system.   If you replace the power supply, get a high quality unit with active PFC => I'd recommend a Seasonic (http://www.newegg.com/Product/Product.asp?Item=N82E16817151027) or a PC Power & Cooling (http://www.newegg.com/Product/Product.asp?Item=N82E16817703005).

However ... before replacing the supply, you DO have the fans blowing in the wrong directions (as noted above) ... so switch them to the correct airflow directions and see if that resolves this.   In addition, I would run MemTest-86+ (www.memtest.org) for at least an hour as a confidence test on your memory.

... finally, the reboot (especially while doing a virus scan) COULD be a symptom of the Sasser virus.   Your antivirus program should have prevented this (it's a fairly old virus) ... but just in case, download the Sasser removal tool and run it:  http://www.symantec.com/security_response/writeup.jsp?docid=2004-050114-1706-99

Author

Commented:
Well, I need to post an update here and see if there are any more ideas. I've reversed the fans, so the input is on the side panel, and the output is on the back. I've also upgraded to an Ultra XConnect 600W PSU... Running SpeedFan, it seems the CPU temp is getting to around 55-57C when it reboots. All 3 fans are working, with the 2 fans that can be controlled running at about 2400RPM. (The third being connected by a regular 4-pin Molex connector). Any more ideas would be greatly appreciated. Thanks.
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Commented:
55-57C doesn't seem too bad for a Pentium D.

What kind of video card is in there? Does it have a fan?
Chris BRetired

Commented:
It isn't heat then. Download and run memtest86. Ram can fail anytime.

Chris B
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Commented:
did you check the power needed?
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Commented:
did you check the power needed?
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