My iPad don't have sound

Have you got notifications muted ? Only notifications (including games) get muted, so the Music and Videos apps, and headphones, still get sound.

Depending on what you've got Settings > General > Use Side Switch To set to (mute or rotation lock), then you can mute notifications by the switch on the right hand side of the iPad above the volume switch, or via the taskbar : double-click the home button; slide from the left; and it's the icon far left; press home again to exit the taskbar. The function that isn't on the side switch is set via the taskbar instead : http://support.apple.com/kb/HT4085

Make Sure iOS is updated to the latest version

Reboot the device by pressing and holding down the home and sleep/wake buttons (power) at the same time until the apple logo appears on the screen, then let go.

If that doesn't work then reset the device by going to settings/general/reset/reset all settings

If that doesn't work, then update iTunes on computer, backup device to iTunes, then restore the device.

If you have already restored as a new device, and not from a backup and that did not resolve the issue then a repair may be necessary.