Randomly, my Dell Vostro 1500 laptop will make a beeping screeching sound coming from the hardware somewhere (I use headphones so it's definitely not coming via speakers). It doesn't seem to be at a time of particularly high CPU usage, and happens perhaps once a week. The beep is very high pitched (perhaps 2500Hz), 3x in about 0.5 seconds and then changes to a lower pitch somewhat tortured sounding beep/screech that starts at about 600Hz and steps (not gradually) to about 650Hz over about a second. The whole thing is a constant sound, with no gaps or staccato beeps. It seems to come from the main fan area, but does not sound like a mechanical noise.
Any help would be very much appreciated