Before you buy a new cell phone or new tablet, please try the following procedure to repair your device. First charge your battery, backup your important data if possible and in most cases take out SIM and SD card before factory reset. It is impossible to recover your data after doing a hard reset, so online backup is always important. For all of your data, a backup should be done on an external device, hard drive, raid system or media. With or without insurance, if your cell phone lost, damaged or stolen at least your invaluable data is backed up in a safe place. If you are about to sell your phone and you want to wipe your personal data, or if your phone affected with virus you have to do a hard reset. In some cases, you can delete the forgotten password or lock pattern from your device as well. All information is for devices with stock based ROMs. If you are using rooted device, always back up your EFS folder first, containing your IMEI info, etc.!
Samsung P7100 Galaxy Tab hard reset
Your device freezes or has fatal errors If your device freezes or hangs, you may need to close programs or reset the device to regain functionality. If your device is still responsive but a program is frozen, close the program using the task manager. If your device is frozen and unresponsive, press and hold [POWER ] for 8-10 seconds. The device will reboot automatically. If this does not solve the problem, perform a factory data reset. In Menu mode, select Settings → Privacy → Factory data reset → Reset Tablet→
Samsung GT-P7100 Galaxy TAB hard reset with keys
With the Samsung Galaxy TAB turned off, press and hold the VOLUME UP button, and then briefly press the POWER button. In recovery menu select wipe data / Factory reset using Volume button.
Note: If you see "Downloading" on the screen with an Android shoveling you pressed the wrong Volume key. Remove and reinsert the battery and try again.