PSU noise

[Kankykur7]

So every time i shut off my computer, psu being a 750w pcp&c, i get this high pitched noise. it reminds me exactly of when you blow a fuse in your house. However, I still can get into the mobo bios and windows fine. I just installed everything today and the first time i shut down the computer it did this. Is it the power supply itself or possibly another part of my system?

thanks