Many Thanks to ukbobboy01 and peerless...

I would tend to agree with you but as soon as I close LW, it does not happen again. So it makes me think that the fan speed is directly related to LW running or not.

Again, it only happens when LW is running in the background AND when the screensaver is active. Otherwise, under normal circumstances AND even with LW running, if I am actively using the computer, the CPU temperature is fine (I tested it with a program called speedfan) and I hear no fan noise.

Very strange....