Motherboard makes a sound

High everybody,

I have a Gigabyte moderboard GA-EP45-UD3L with a core 2 quad Q9600 with 4GB Ram Corsair 1066Mhz

When I am using my computer, it makes this sound, the same sound that motherboards do when you shut them down, but the problem is that the pc does not shut down, it keeps working. I don't know what the problem could be. Could you please guide me? Thank you.

um.. the only sound I ever hear my mobo make is a beep on post.. please explain the noise.. all my noises are fans!

It is the noise of shut down, I don't know how to explain it. My god. It's like my pc shuts down but it doesn't shut down. It continues working

Are you sure the power button is connected to the correct place on the board? I don't know your board but does it have a power switch built onto the board also? if so are you able to turn it off using that switch?

Problem fixed. It was my hard drive that was making the noise, not the motherboard. Sorry, may bad. I disconnected the hard drive from the mobo and problem solved. Thanks for your replies.