Board, Ram or CPU? Boot loop with no display.

Fish_Fish

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Dec 29, 2012
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My PC was running fine, but now it won't boot unless I remove 3 of the 4 RAM cards.

It will boot with one 4GB RAM installed, and it will do this with any of the RAM cards, but with two or more it won't boot.

By won't boot, I mean, it shows nothing on the display, no bios, nothing. But it does try to boot and keeps restarting.

The mother board is Z68 (MSI 7681)
Ram is 4 x 4 GB CORSAIR Vengeance
CPU is i7 2600k @3.4 GHz

I have already replaced the power supply, with no luck. Stripped it back to minimum installation which is how I found it could boot with one RAM card. I have reset the CPU with a new CPU fan, but no luck.

Question is... does this sound like the motherboard has gone, the ram has gone or the CPU has gone?
I am kind of suspecting the motherboard, but how can I know????
 

str8cuse

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Dec 29, 2012
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Are you using on-board video or a graphics card? Any lights or indicators on the motherboard showing a fault? Beep codes?
 

Fish_Fish

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Dec 29, 2012
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I'm just using the onbaord video card, no additional video card.

With more than 1 RAM chip installed: 6 LED's come on as they should, but just for 1-2 seconds, then they die out, there is a very quiet beep, and a few seconds later the computer tries to start again, on an endless loop. It does not get far enough in the bot process to display anything on the screen. The LED's don's appear to indicate much, just "CPU is in 6 phase power mode".

With 1 RAM installed it boots fine.
 

str8cuse

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Have you tried installing the ram in each individual slot? that is..put it in dimm_0..start the pc. the next time try dimm_1 etc. If each slot works with the one stick of RAM installed you might want to see if there is a bios update for your motherboard and it wouldn't hurt to check to see if your motherboard has a "supported memory manufacturer" list. Also, could you list what your power supply is?
 

Fish_Fish

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Dec 29, 2012
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I tried one ram into each slot one after the other. In either slot 1 or 2, the PC boots fine. In slot 3 or 4 it wont boot.
I also noticed that with two ram chips, if they are in slots 1 and 2, the PC wont boot but more just hangs there not looping, but not getting to any boot screen.

Before all this the PC was running fine with 4 x 4GB ram for about 1 year. But the power went a few months ago so I swapped to an old cabinet. Again it worked fine, till 1 week ago, now I have replaced the cabinet with a new "Cooler Master" with a new 500 watt power supply.

My main questing remains, does this booting problem sound like the Motherboard has gone? Or could it still be ram or CPU related? I don't mind changing the Motherboard, but would be a bit gutted if it doesn't cure the problem! :(