I have a '94 325i Convertible.

I get CODE on the radio sometimes. No apparent rhyme or reason. I input the
code and the radio works fine.

The window -- driver or passenger door -- loses its Home Position, and
thinks it is fully raised. When the door is opened, the window will drop --  
as if the window is fully raised -- then go up when the door is closed.
(Dropping and raising is normal IF the window is fully raised when the door
is opened, but my windows will behave this way even if the window is fully
down, and will repeatedly behave this way until the window actually reaches
the top.) The Convertible windows work the same way as the coupe windows,
the sedan windows do not have this behavior. This is a random event too. If
I intervene by operating Window Switch, then the window will behave properly
until it forgets where it is again.

When I set the Ignition to START, the car does absolutely nothing. I have to
turn the key to OFF then START again, and it starts properly with no
indication of any weakness. This is a new behavior. The first failure was
noted in the radio CODE, then the windows began to do strange things,
finally the ignition started to flake out.

Twice in the past 10 days, or so, the Emergency Flashers started flashing
for no apparent reason, as if the car was reacting to being in an accident.
These instances came about when the car was parked, and I thought my dog had
stepped onthe flasher button, but the button was not depressed so the dog is
not the problem.

I thought this was an indication that the battery was getting weak, but I've
been told this could be a sign of problems with the immobilizer.