Oly is right on the mark on this one, as someone who does these exact repairs I can tell you it is very difficult at best to identify a bad component and replace it on a motherboard. Your best hope...

You should first try and determine where the noise is coming from as it could be a bad CPU fan or something else that will follow you to a new case or is need of replacement.

That being said, most...

How many drives, fans and usb devices are you running? The more of those the more power draw you are going to experience in spikes especially hard drives which can start up and as a result draw more...