Here are the steps to perform the reset:
1. With the device off, press and hold Volume Up and Power.
2. Release the Power button when you see the Samsung logo, but continue to hold Volume Up until the recovery screen appears.
3. Use the Volume buttons to navigate the menu and select wipe data / factory reset. Press Home to choose the selection.
4. Press Volume Up continue.
The Galaxy Tab should then go through the hard reset process.