New build does not boot, need help!


Jan 7, 2009
Hello all, this may be long so bear with me.

Motherboard: ASUS P8Z68-V Pro
CPU: i5 2500k
GPU: GTX 570
RAM: 2x4GB Corsair Vengeance
PSU: Corsair AX750

This is my first build, and I screwed up big time. Here is what happened:

I connected everything correctly, my last connection was my two front 120mm fans. I didn't know I was supposed to connect those directly into the PSU, so rummaging through my PSU cables, I found a cable that resembled a 4-pin molex into a 4 pin connector, so I connected that to CHA_FAN on my motherboard. Little did I know, that was a FFD cable for floppy disks, so when I turned it on for the first time, I heard a loud POP! At that time, I was still getting a display on my monitor saying, "Detected new CPU, etc. Press any key." I didn't want to go on because of the POP so I turned it off.

What happened next:

Did some research and realized I might have blew something because I used the floppy disk cable for the fans, I pulled it out and tried to boot again. This time, it seems like everything is okay. I went into BIOs, all the voltages are right where it should be, I installed Windows 7 and was at the product key page when suddenly, my brother-in-law walked by, tripping over the 30lb air purifier unit, knocking out the power from the air purifier and knocking out the power from my computer. I thought he probably pulled the power out of my computer so I just turned my computer back on.

What happened next:

When I push the power button, the GPU fan spun at 100%, sounded like an aircraft taking off, and I got no signal to the display. My computer would turn on for 2 seconds, shut off for 5 seconds, turn back on, remain on but no display. It would keep doing this, leaving my GPU fan at 100% the entire time. I plugged my DVI cable into the motherboard's onboard video, and I got signal to display, so I thought it must be the video card. I put in my old 9800GTX+ GPU into the motherboard, and again, no signal from GPU. The test lights would turn red all over my motherboard so I thought it was the motherboard, so I got an exchange.

What happened next:

Got a new replacement motherboard, connected everything, pressed power button. GTX 570 fan shoots to 100% and again, no display. System would turn on for 2 seconds and reset itself. Connect old 9800 GTX+ into new motherboard, and I get signal. So now I'm thinking the GPU is toast too. I go into BIOs, and notice the 3.3v for CPU is in red at 2.8v and CPU idle is at 40c with my Corsair H60. Now I'm thinking it's the PSU too because of the initial floppy disk cable fiasco.

I don't want to keep returning and exchanging, if I don't know what the problem is. I don't really have the tools to check. Does anyone know what the problem is from the events that happened? I'm sure it is just one part.


The Corsair brand is pretty reputable, but abrubtly disconnecting power from the PSU can often cause internal damage. I would first disassemble your system, and then breadboard it (build outside the case).

Whether or not your monitor display works with the 570, check the voltages on the PSU by means of a digital multimeter.

Check the link in my signature for detailed instructions on breadboarding and PSU voltages.

Good luck.



Not always the case - it could be the motherboard, it could be the power supply, it could be something else entirely. Was this a new PSU for this build or were you using it for a previous build?

What you could try doing is disconnecting all chassis fans from the motherboard and running them through the power supply, that might solve this issue. You could also swap PCI-E power cables for different connectors and see if that works.

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