Ipod5 goes off randomly, with little lines as if a glitch. HELP!

Wifi doesn't always respond. Itunes recognizes it.

Updated to ios 7.0.4. Two times restored to factory settings & DFU mode. It just goes off and on when I am on internet, music or an app of games.

battery is always charged. Time always changes. Never has been jailbroken. Had it since april. 2 weeks ago it started suddenly when I was in facebook, apparently the password for the account was wrong or something happened, the ipod asked to the password be written again. It just freezes and then blackouts and the apple logo appears. Don't know what else to do. I know it may be a harware issue, HELP want it back!