Volume bar disappeared on ipad

Try a reset a few more times.

Hold the Sleep and Home button down until you see the Apple logo.

Try:

- Reset the iOS device. Nothing will be lost

Reset iOS device: Hold down the On/Off button and the Home button at the same time for at

least ten seconds, until the Apple logo appears. done

- Reset all settings

Go to Settings > General > Reset and tap Reset All Settings.

All your preferences and settings are reset. Information (such as contacts and calendars) and media (such as songs and videos) aren’t affected.

- Restore from backup. See:

iOS: How to back up

- Restore to factory settings/new iOS device.

Check Restrictions. Even you did not turn Restrictions on, turn it on, check about volume settings then turn Restrictions off again.

Hope it helps