Just got my old PC up again while I wait for my new videocard.

Got everything updated (nForce2 drivers to 2.45, latest board sound, latest forceware for the 6600gt), but im getting some weird noises. I use high quality headphones (Sennheiser 280 HD Pro), and I can clearly hear how when I move my mouse, when a FAN changes its RPM, HD activity, when I min/maximize windows, scroll down up windows etc, strange noises. I can notice it also with the speakers, less, but I don't care since I want to use the headphones.

Is just really annoying, you can hear it even if you mute EVERYTHING from the volume controls. I connect the headphones at the green jack.

HELP please.

I had the exact same mobo with the same problem.
Its because of poor isolation of the on-board sound. Mine was fine at first, but got worse with age. Im not sure what could have "worn out" but I had no fix.

BUT, make sure you have a good clean power source, and that things are all grounded nicely.

My fix was to get a sound card.