Strange electrical problem (stereo related)

[99CSVT]

Late last night, I went out to my car to find the antenna extended, and the radio on playing music. Strange part was that I wasn't in the car, nor was the ignition turned on. My keyfob didn't work either. Once I unlocked the car and opened the door, the radio turned off. What I'm asking for is if anyone else has had this problem and/or where would be a good place to start looking? As always, it is much appreciated! Thanks!
Sean

 

[Tony2005]

Start by charging the battery well. Then test it. A bad battery does weird things to the car.
http://www.contour.org/ceg-vb/showthread.php?t=3535