electrical errors on my 745

[carmadgeof]

Hi does anyone share my experience of electrics going funny on 7 series my 2002 - the early cars?
I've ahd the sat nat disappear and then come back. When I start the car often comes up no cd in nav system. Occasionally the hifi goes literally crackers! At the moment the cd changer not doing anything flap opens and then closes the mag won't come out.
Geoff