Hi, my computer makes a loud humming (medium - high pitched) when it is on. Doesn't stop. Its quite annoying and is louder than most computers ive ever seen. I dont believe the video card has a fan either (GF 2 64mb)... any problems ??
Check the processor fan. See if its coing from there. If it is, blow out any dust on it. If that does not help, then that is the sound of the bearings in which case, I would replace it or deal with it. Post back your results.