Reason Behind Power Supply Poping and Arcing Nosies

[PeterPorker3]

I recently picked up a computer (i5 661, 5gb ram for some reason?, integrated GPU) that wasn't working to see if I can get it working again and potentially sell it. I found the main issue, one of the memory DIMMs came loose, but there was another problem. The power supply makes this horrific, loud screeching and poping noise whenever the hard disk activity light blinks. It kind of sounds like electrical arcing. This already discourages me from selling it with its original power supply, but I can't help but wonder what is causing this. The reason behind my curiosity is that I recently bought a laptop off ebay, and the included charger made the exact same noises. Does anyone know what is causing these terrible sounds, and does it really mean the power supply is unsafe to use?

[emosun]

throw it away and replace the unit

[PeterPorker3]

10 minutes ago, emosun said:

throw it away and replace the unit

I'm already doing that, but what component in the psu is making that sound? A Coil Maybe?