2006 pt cruiser radio cd changer sometimes not turn on

I have a 2006 PT Cruiser that sometimes after turning the key on, the radio will not turn on, but all other dashboard area lights and things seem to be working. What could be the cause?
When it does turn on, are all the preset stations still there?
You may have a faulty connection to your power accessory, which could be wired to your ignition or cigarette lighter. To be honest, it could be anything, I am just speculating an easy fix. Probs best to take it to an Auto Electrician in your area.