Keeping restart after 3 songs

What kind of ipod or Mp4 player do you have? Please note that genuine Apple iPods Do not say MP3 or MP4 on them. You can put your serial number into https://selfsolve.apple.com/GetWarranty.do  to see if you have a real apple iPod.
That said, you should probably try reformatting it. To Do this, Right click the drive in itunes and click format. If the player shows up in iTunes, click restore when it pops up. Please note that this will destroy all data on the player.