electrical issues with focus

hello I have a 2005 ford focus. my wife complained that her radio was acting funny. it was going on and off, the cd changer kept trying to change well I rode in it and turned radio off. after filling up with gas I turned car on and radio was on again(we had not turned back on). it was doing all kinds of strange things as above. I turned it back off. once we turned car off. it will not start. there is no electrical power to car except if I turn key the starter would turn as if trying to start the car. but no lights, radio, buzzers, and car wont start.