White Noise/Static Nosie comming out of my speakers/headphones

[Cold_Finger]

This problem has been going on since I bought my computer from Fry's Electronics. I eventually got used to it, even when it gets really loud.
But it turns out that my microphone picks up the noise it makes when I'm on Skype, and my friends are getting annoying by it.
This is why I am trying to get it fixed.
I don't know why it happens or what is causing, but I'm guessing it is my power supply. Whenever I trying running an game that uses more power such as Grand Theft Auto IV, Crysis, or games along those lines, the annoying static sound comes up.
Here's an example:
[media]http://www.youtube.com/watch?v=f_AizWYI5EY[/media]
What could I do to fix this without changing to a new power supply?
Specs:
[IMG]http://i.imgur.com/O1NYP.jpg[/IMG]
My power supply supplies around 750 Watts.

[bowedyapper]

It could be many things, I did experience a similar problem to yours, but it was not as extreme, if I had my TV connected to my graphics card as well as my monitor, I would get a screechy white noise when using GPU intensive programs, and the pitch would change depending on how much load the card was under.

This was due to power from the TV going to the graphics card, then through the case, and to the speakers, I would suggest you try disconnecting things you don't need and test games again.

You could try disconnecting anything which is connected to your computer that requires an external power supply, e.g. External Hard Drives, Ethernet cables etc.. and see if this noise still exists, if it does, try launching a game and when the noise starts, disconnect your monitor, if it still persists, then I am unsure what the problem could be.

EDIT: I also found this to be the case with another pc connected to the same outlet / sockets as my own, so isolating your pc to a single socket could be a good idea :)