Why is my phone not play anything?

My problem is this : my phone is not playing music ( when I put a song passes from one to another without reproducing sounds) , does not play video (when I try to play says you can not play or that the video is damaged ; when it comes play videos from youtube happens that does not play the same) , it does not take photographs or video and sounds that come with your phone as rintones also reproduces ; I think the problem comes from software and what I did was restart the phone ( default setting) but still the same , now the phone does not have video files , music, pictures or anything and as usual , what 's wrong ?