I recently upgraded my computer's power supply from 350w, to 500w, but after running it for a few hours, a very loud high pitched noise started coming from the computer. So I swapped the 350w one back in, and the sound still hasn't stopped. It starts the second the computer is switched on, and stops when it is turned off. It's not any of the fans, as I have checked them.
The sound stops when the graphics card is out of the motherboard, and it stays off regardless of it the 6pin power supply is in or not.
The graphics card is an NIVIDIA GeForce 8800GT and the motherboard is a Foxconn 45GM.
I really need some help with this, so if you need any other info, please
let me know.