What is this strange sound on my pc?

My pc is working fine , no problem at all but sometimes it does make this sound and i don't know why.

Could it be feedback from the internal mic setting enabled and set too high? Might try disabling the mic in the Sound settings, unless you are using it, or simply turn your volume down if you need the mic, and see if that eliminates the feedback.

remm said:

Could it be feedback from the internal mic setting enabled and set too high? Might try disabling the mic in the Sound settings, unless you are using it, or simply turn your volume down if you need the mic, and see if that eliminates the feedback.

I cannot figure it out because it does not do it all the time if it was doing it would be easily to find.