Hello there. I'm posting because I'm not sure what's wrong with my friends new pc that I just helped him build yesterday. Everything was setup, hooked in, ect, but when we hit the power..it wont power on. First we thought it might be the PSU, because it is making a high pitch noise when we turn on the psu (the fan nor the LEDs turn on aswell) Although, we did the PSU test by jumping it to see if it would work, and when we did that, the psu gladly started up, spinning fan and bright LEDs. We also hooked it up with a DVD drive and that worked fine too, so its not that.

When we hook the main powers to the motherboard in however, the high pitch noise returns and it doesnt power on. We tried various combinations, like taking out all the unnessisary things such as the dvd drive power and such. It still wouldnt work. Theres also a manuel power/reset button on the motherboard. We tried those and they didnt turn it on either, so its probably not the case connections.

So does this mean that the motherboard may be defective? What else might cause it not to power on at all...

Thanks in advance

You may need to pull the motherboard and make sure it is not touching the case at any point. That will cause the motherboard to short. To check the board, cut a piece of card board slightly bigger than the MB. Place the MB on the card board. Carefully reinstall your memory and video card then hook up the PSU and apply power. If it still does not power up then it is a safe bet the processor, MB or both need replacing...

LC

Hi The high pitched noise could be a leaking or faulty compasitor on the mainboard if the mainboard is new and still makes the high pitched noise after what Lord Chance said to try it will be a faulty mainboard.