Computer reboots randomly even before windows loads

March 16, 2012 at 02:13:19
Specs: Windows 7
Hello,
This thing started a few days ago.
My computer can work normally for hours and then it just shuts itself down and then reboots.
It then may load again or get into endless reboots. Sometimes the BIOS doesn't even get to POST before the computer shuts itself down.
Then after a few hours when i turn it on, it works ok.

I've checked CPU/CASE temps after this and they are normal.
Checked all fans are operating. Checked heatsink is placed correctly on CPU. Checked memory modules.
Tried connecting the computer to another outlet.

Its a desktop computer with gigabyte motherboard, hec PSU, 4 GB crucial memory.

Would be glad to get any help before I start spending money on a new computer...


See More: Computer reboots randomly even before windows loads

Report •

#1
March 16, 2012 at 02:32:10
"Checked heatsink is placed correctly on CPU"

Did you disturb the heatsink to check it? If so did you clean off old thermal paste and re-apply fresh?
What spec powersupply? Total wattage and AMP ratings on each voltage rail ?
Download the ISO image for Memtest86 and burn a bootable CD of it.
Boot up to this and test your ram. Remove all but 1 stick and test each stick separately then test together.

Goin' Fishin' (Some day)


Report •

#2
March 16, 2012 at 05:07:39
Memtest, definitely yes. I prefer together, then separately if errors. no errors are acceptable.
If heat sink was disturbed, definitely reset right.
FULL spec please. Power supply make, model, and ALL numbers (wattage AND list 3.3V, 5V, & 12V Amps on all rails separately) and all components installed, especially graphics card make and model. List the temps.
Try booting into BIOS set up to see if that is a problem and check temps, etc. there at start up, wait a few minutes to make sure they are stable, then boot to windows.
Report results.

You have to be a little bit crazy to keep you from going insane.


Report •

#3
March 16, 2012 at 07:22:12
Didnt apply fresh paste just made sure the old paste is placed correctly.
More specs:

Motherboard - gigabyte GA-P35DS3L
Psu - hec ATX-5400tz (400w)
Cpu fan - igloo 5600pwm
Mem - OCZ PC2 6400 gold edition XRC 5-5-5 2GB. X 2
Graphics - Lantic geforce 450GTS

Now when i turn on the computer the screen doesnt turn on (no video signal)
And the cpu fan goes to maximum.

Any idea whats wrong???


Report •

Related Solutions

#4
March 16, 2012 at 07:56:48
Whenever you remove a heatsink you must clean of old paste and re-apply.

Googling is quicker than waiting for an answer....


Report •

#5
March 16, 2012 at 08:51:38
Psu - hec ATX-5400tz (400w) = JUNK, if you have another know good PS, I would try it.

larry


Report •

#6
March 16, 2012 at 09:03:51
"Didnt apply fresh paste just made sure the old paste is placed correctly"

There's at least part of your problem. Once the thermal bond is broken, the old thermal material MUST be completely removed, then fresh thermal paste applied.

"And the cpu fan goes to maximum"

That pretty much confirms that the thermal paste is the problem. Find your CPU on the following list & read how to re-apply the paste properly:

http://www.arcticsilver.com/intel_a...


Report •

#7
March 16, 2012 at 09:13:10
Ill try to reaplly a new paste, but still, thats not the inital cause of the problem..

Report •

#8
March 16, 2012 at 11:45:17
You were asked for the power supply specs in response # 2. The make/model doesn't help much, except that hec isn't known as a quality name brand.

Report •

#9
March 16, 2012 at 12:13:16

Report •

#10
March 16, 2012 at 15:32:37
Clean off old compound and reapply, follow these directions:
http://www.arcticsilver.com/methods...

Your graphics card (or similar ones) run around 127Watts or over 10Amps, mainly off your 6pin PCIe connector. If the power supply did not include one of these. what connector or adapter are you using? You should be using an adapter that uses two Molex connectors Y'd into the 6pin connector and you MUST use Molex connectors from two different wire runs, NOT two on the same wire (meaning one above the other on the same run) so that the load is not on the same set of wires and on only one of your 12Volt rails. Better would be for you to get a power supply that has only a single 12Volt rail, is certified as 80% or more efficient, and has active PFC from a quality name brand that has at least one 6pin PCIe connector already.

You have to be a little bit crazy to keep you from going insane.


Report •

#11
March 17, 2012 at 02:21:04
The 6 pin pcie power connector is connected to 2 seperate molex connectors. One is combined with the HD. The other is combined with the dvd-rw.

The computer has operated without problems for 2 years.


Report •

#12
March 17, 2012 at 07:56:59
well im going to buy a new PSU hoping to fix the problem.
Any reccomendations?

Report •

#13
March 17, 2012 at 20:01:48
Look at this one:
http://www.newegg.com/Product/Produ...
Or if you want more power for a future graphics upgrade:
http://www.newegg.com/Product/Produ...
The most important is Quality, Single 12Volt rail, 80%+ certified, Name brand, Good Warranty.

You have to be a little bit crazy to keep you from going insane.


Report •

Ask Question