1997 740il speakers quit

[lastbone]

I'm new to the BMW world and have just purchased a 1997 740il, which is a fantastic ride. Everything seems to function correctly except the stereo speakers. They work fine for the first 2 hours, but then go silent for around 6 hours. Once the 6 hour sielnce is over, the speakers are fine for another 2 hours. I suspect it has something to do with the theft deterrent system, but that is only a guess.

Also, the inside trunk release doesn't work at all. The remote key release works fine, as does the actual key. Could the two problems be related?

Any ideas?