problem: high-pitched, semi-soft but always noticeable whine when speakers/headphones are plugged into the case jack. includes random extra noises depending on system activity - crackling and buzzing re fans and hard drive activity, whirring as cd drive spins up/down, a strange beeping when i minimise/maximise windows etc.

specs: intel desktop board d945gtp with integrated intel hd audio (don't laugh!)

really hoping this can be fixed with some sort of case fiddling - it's infuriating! any help or directions to help would be vvvvvv appreciated.

typical for onboard audio. Try muting everything but the wave and master. You'll probably still get the noise problems, so the only real solution will probably end up having to be a purchase of an audio card / usb/firewire audio device.