I'll preface this by saying I have very limited knowledge when it comes to cars.
I bought a Ford Focus 2003 auto about 2 months ago. The two times I tried the car out everything was great with it, no issues at all. I drove the car home, parked it and just an hour later when I tried starting it it was dead. The key turned, the radio started playing and the dash lights turned on, but when twisting the key all the way I would just make a slight start noise then go flat. I thought I might had left the lights on, just I charged the battery. The car started up again and ran for about 4 days; I was driving when all of a sudden they radio starting turning on and off by itself. When I parked the car and turned it off, the same issue as previously happend and the car wouldn't start.
I then bought a brand new battery, and this lasted me for about a month. When driving the other day, the radio started acting up and turning of and on again. Im charging the battery as I'm writing this, but doing that all the time isn't really a fix to the problem. Has anyone had similiar issues and know what the problem is? I'm thinking it might be the dynamo that broken, but as I said I have no idea. Thought I'd rather ask here first then take it to the shop if its an easy fix.
Thanks in Advance.