thanks for the reply , I remember dialing the wrong number once on my telephone and getting a fax line ,this noise reminds me of that ,just a few notches higher in pitch ,but it has a sort of warble to it like the fax tone.
there is no motherboard speaker so I cannot remove that ,I can here it on my headphones quite distinctly .removing the headphones does nothing though and I can still hear the sound eminating from the general area of the PC , I will try switching the mouse/keyboard to another usb socket (pair) and see about that , could the monitor be giving off this sound ?