I second to that. Remove your media card.
If its a new one, put into your phone and when the system boots up,
race to the options, click "media card" click "menu" and click "format card"
If its a card with plenty of data, back them up on your com. RECALL what's the last files u put in before the problem occurred. The remove those files.
If not, back up. After formating, put the files back in one by one. Surely one file, after putting it in, the phone will have the same problem. Just remove that file.
I fixed my problem last week with the aboves steps. mine was restarting every 5 minutes too.