Asus motherboard audio - high-pitch noises

[Purino]

Hi guys,

I built a pc with the Asus P5N-E SLi nForce 650 (Socket 775) PCI-Express DDR2 motherboard from OcUK. The onboard audio works most of the time, but when some programs are running (like games), it gives off high-pitch noises. Mostly it happens as soon as the programs start opening.

I know almost nothing about audio on pcs, but if it helps, it came with Realtek HD Audio Manager.

I'd really appreciate some advice as to what I can do to locate the problem.

 

[Purino]

Just put the mic properties to mute, unfortunately I still get the sound. The weird thing is the sound changes depending on what's happening on screen, so if the program's main menu has a moving object in the back, the sound changes as it moves. It affects lots of programs, old and new.

The high-pitched noises only stop when you change the screen, otherwise they are constantly there.

Anyone experienced this before or am I getting communications from outerspace?

 

[Purino]

Thanks for your descriptive answer Monkeynut! I'll buy a new reliable external card.