Oh dear.... my new PC won't POST :(

[Defenestration]

I have been pretty happy with my new E4300 P5B Deluxe system and had it OC'd to 350 FSB where it was stable at 1.4Vcore. Because I wanted to get the most out of my 800MHz RAM, I thought I'd try lowering the multiplier from 9x to 8x, and then upping the FSB to 400. This worked OK and so I thought I'd try a bit further - 415 worked OK too, but when I upped it to 420 it POSTED and booted OK but then the system shut-down after about 5-10 seconds of Orthos.

Now when I start the machine, the fans start but after about 5 seconds it shuts off automatically for a couple of seconds and then restarts automatically and stays powered on with fans but nothing happens.

It doesn't beep and it doesn't POST. The monitor does not get any signal (ie. light stays amber)

I have tried removing the battery and clearing the BIOS for about 10 seconds which didn't work, so I tried clearing it for 2 hours including removing the 2 x RAM sticks and that also didn't help (I did try each RAM stick individually).

I will now leave it clearing overnight to see if that solves the problem. However, in case it doesn't I wanted to see how I should go about determining what's gone wrong, so I can RMA the correct part.

All the parts are new, and I only have a laptop so it's a bit difficult testing each component in a new machine, hence the request for ideas on determining which component is dead.

I may be able to borrow someone else's machine to try the components, but that is not a definite possibility.

Help!

[Clunk]

Unplug the wire out of the psu, turn it off, short cmos, remove battery, remove ram, press power switch a few times sto discharge, leave overnight.

Hopefully itll work.

Or remove the cpu and then power on for about 20 seconds. refit the cpu and try again.

[Defenestration]

If that doesn't work though, any ideas for determining which component is at fault ?

I have a feeling it might be the mobo, since I never got above about 380 FSB when using the 9x multiplier.

My fingers and toes are crossed in the hope the overnight or CPU removal technique will work though.

[Defenestration]

Also, have you ever had this problem where the overnight battery removal/cmos clearing didn't work, but the CPU removal + power on for 20 seconds did work ?

[Clunk]

Try both of them. If one doesnt work, try the other.

You say you have tried one stick of ram at a time in all of the slots?

And, are you sure you are clearing the cmos with the correct jumper?

[Defenestration]

You say you have tried one stick of ram at a time in all of the slots?

And, are you sure you are clearing the cmos with the correct jumper?

Yes to both questions.

Would I be right in thinking that because the mobo doesn't beep, then that indicates the mobo is at fault ?

or, can this also happen if another component is broken ?

I said it might be the mobo, but it's also possible it could be the CPU.

[DR]

I'd be surprised if the mainboard has just failed from this small overclock.

Did you mess with the voltages at all?

Try the unplugging of the power, as suggested above

[Defenestration]

I had RAM voltage set to 2.1 which is what is printed on the RAM sticks. I had also upped VCore to 1.4375.

[Defenestration]

Unfortunately, clearing cmos overnight didn't work, so that just leaves the CPU removal.

I think I might end up having to RMA the motherboard followed by the CPU, and pay for return shipping if the mobo is found to be working

[DR]

Have you got any other components you can test with?

[Defenestration]

No other components - that's half the problem.

Does the P5B Deluxe beep if you try to boot with no CPU ?

Likewise, does it beep if there is no RAM ?

[Clunk]

It should beep if there is a cpu and no ram. I cant remember if it beeps with no cpu in, I think not though.

When you tried to reboot after leaving it overnight, did you try it with 1 stick?

[Defenestration]

When you tried to reboot after leaving it overnight, did you try it with 1 stick?

Yes, I tried each stick individually in each of the four slots.

[Clunk]

Next thing I would do is take the board out of the case and build it up on some cardboard to make sure there are no shorts in the case.

This P5N32-E sli that I have had a backplate that shorted out, and I had to trim it down before it stopped, so its worth looking at that.

[DanceswithUnix]

A few months ago I bought a CPU + mobo + ram from which died within 15 mins of first power up (no overclocking involved, just flakey). I just RMA'ed the lot, and let Scan do the testing and sorting out.

Turned out it was a duff mobo that was blowing the CPU, so sending both back was handy.

They even paid for collection and return postage, I was most impressed.

[Thorsson]

I see that you have the popularly recommended Corsair PSU, which should in no way be stretched by your activities, but I've had similar results (spinning fans, but no post) when the PSU has died.