what causes a ringing bell sound from the dash area of a bmw

Frost Warning? Did the temp get down near freezing?

Jeff could be right on this. There is an audible alarm that is set to sound at 39ºF to warn of possible icing. There is also a snow flake display that can be displayed if this is the case.

there must be a warning light some where other wise its a computer problem can be more specific if you give the spec. of your car,

could also be the hourly alarm, you can accidentally turn it on using the S/R button, if there is a little symbol in the upper right hand corner that is your problem, just hit the S/R button once to turn it off