Summary

We are not aware of any virus that would play the song "Fur Elise". However, some PC motherboards play this tune when there is a hardware problem. Check your motherboard manual.

For more info, see the homepage of Diamond Flower Instrument: http://www.dfiusa.com/music.asp :

        Musical Warning

        Damage Free Intelligence (D.F.I.) is a feature we have added
        to our newer motherboards to warn users of some classes of
        hardware related problems.  It is a warning system on the
        motherboard that plays a warning tune if certain hardware
        problems are detected.

        Some users hear strange music coming out of the PC speaker and
        think they have been hit by a virus - they scan the hard drive
        multiple times and reformat it, but it just will not go away.
        The user now thinks that they have been infected by a virus
        that no virus scanning software can detect today.  This is not
        the case at all.

        The standard alarm/tune/music that they may hear is a
        variation on "Fur Elise." Our production motherboards use this
        tune whereas pre-production/prototype boards may use other
        sound chips.

        There are three main sets of reasons that the alarm/tune is
        playing - Processor, Heatsink/Fan and Power Supply related.

[Mikko Hypponen]