My radio howls when turned on continuosly. I suspect it is the radio anti theft system that is activated because the battery was disconnected for three months. Do anyone knows what I have to do to stop the continous howling?. Please, help.

Howling Noise? I'm assuming that this is engine noise from the electrical system. You have said that the battery was disconnected for three months, my suggestion is that your battery or alternator is going to need replacement soon. So... if you can deal with the the engine noise for now, keep driving and keep a pair of jumpers cables with you.