Weird "death" drives me crazy, really tough!

[DarkPilgrim]

I have my computer bought 2 months ago.
It contains parts as below:
CPU: Conroe E6300
Mainboad: Gigabyte 965P DS3(Bios F5, SouthChip C1 vision)
RAM: VData 512Mx2
VGA: Nvidia 7600GT
Disk: SATA 160G
Power supply: 350watts

Last Friday night, It was suddenly dead after being used for about
3hrs.
And from then on, it will be dead at any time, no matter what you do or
what it does.Some times, I even can't boot it up.I list up all features
when it's done as follow:
1)It can be dead when POST is over, and you can see CPU information on
BIOS startup screen.But no more information appears where RAM
information is supposed to appear.
2)Like 1), it may be dead when RAM information shows up.(Coz' I have
them work at Dual Channel, it will be "Memory works at Dual
Channel").It can even die at "Memory works at D".
3)When it checks disk(just after Windows Progress is over), it may die
there.
4)When I get to Desktop, it may die at any time,no matter what I do.And
at most times, it dies in several minutes after into desktop although
few times it runs as long as about 1hr.

There are still important things I need to add.
Before it's dead, no recognizable things happen.And no blue screen or
reboot,even once!
Besides this, sometimes I can't boot it up. I can see all the
fans(including Power supply fan) spin for about 2 secs then stop, then
spin and stop again.

I have replaced the Power supply and buy one UPS.None help. I don't
know what's the hell with this dumb box.
Anyboy helps me!!!Many thanks!!!

 

[Rod Speed]

Most likely a bad motherboard with symptoms like
that and having changed the power supply already.

If you bought it assembled, time to exercise the warranty.

Likely you didnt because you swapped the power supply.

Try with the minimum of ram, just one stick and then
the other to check the unlikely possibility of faulty ram.

Try a RMA of the motherboard.

Worth trying it loose on the desktop just before you
return it in case its an intermittent short to case.

 

[DarkPilgrim]

I tried plug on/off RAM with one stick or two.This can't help.I also
have some guess but no technical proof.

Some times I boot the computer, it turns on and then off, then on,off
again.This can iterate for several times.Given the Power supply is OK(I
think it is), it seems that the POWER GOOD singal doesn't reach
motherboad. So motherboard doesn't stop reset. But this can't explain
why it's dead after entry into Desktop.

Additionally, I mean "dead" by that the screen image is still there but
no response from keyboard and mouse.Does this mean the Video card still
work except the screen image data is not updated.It seems that CPU
doesn't work from then on.

To conclude above, is there a possibility that there is something wrong
with circuits on the mainboard, which are responsible for sending POWER
GOOD signal and supply voltage CPU needs?

 

[Rod Speed]

I tried plug on/off RAM with one stick or two.This can't help.
I also have some guess but no technical proof.

Some times I boot the computer, it turns on and then
off, then on,off again.This can iterate for several times.

Even more likely to be a motherboard problem.

Given the Power supply is OK(I think it is),

Yes, its unlikely to be two bad ones in a row unless both
cant handle the load because they arent powerful enough.

it seems that the POWER GOOD singal doesn't reach motherboad.

Unlikely to be that.

So motherboard doesn't stop reset.

You mean doesnt start. That doesnt explain
why it worked fine for a while and doesnt now.

But this can't explain why it's dead after entry into Desktop.

Correct, if it isnt getting POWER GOOD, it shouldnt boot at all.

Additionally, I mean "dead" by that the screen image is
still there but no response from keyboard and mouse.
OK.

Does this mean the Video card still work
except the screen image data is not updated.

No, it usually means that the cpu has stopped for some reason.

It seems that CPU doesn't work from then on.
Correct.

To conclude above, is there a possibility that there is
something wrong with circuits on the mainboard, which
are responsible for sending POWER GOOD signal

The POWER GOOD signal is from the power supply to the motherboard.

and supply voltage CPU needs?

Yes, its certainly possible that the voltage regulator
on the motherboard that produces the Vcore voltage
for the cpu is what is failing intermittently.

 

[DarkPilgrim]

Thank you very much.And I decide to replace the mainboard by a new
one.Fortunately, the 3-month warrant is not expired.

 

[meow2222]

try memtest86.


NT