Solved: How to reset Samsung Galaxy Mega Android hard reset

Samsung Galaxy Mega i9205 Soft reset

Enter the Android Recovery menu and select the wipe data / factory reset option.
You can enter the recovery menu by pressing these 3 buttons at the same time on your phone.
1. Turn off Galaxy MEGA. Be sure your battery is charged enough.
2. Turn ON the phone by pressing the HOME + Volume UP and the POWER key at the same time for about 10 seconds.
3. The Android Recovery menu will be displayed.
4. Highlight and select - using the Volume down key - Wipe data / Factory reset.
5. Go to next by pressing the power key.
6. Select again Yes -- delete all user data and press power.
7. All your data will be removed. Be sure to backup your data before doing a hard reset.
8. After everything is wiped out select reboot system now - using the power key to reboot the phone.

samsung galaxy mega i9205 hard resetPress and hold for more than 7 seconds to reset the device if it has fatal errors or hang-ups, or freezes.

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 frozen and unresponsive, press and hold the Power button for
more than 7 seconds. The device reboots automatically.

If this does not solve the problem, perform a factory data reset.
use menu option in settings 

On the Applications screen,
tap Settings - Accounts - Backup and reset - Factory data reset - Reset device - Erase everything.

gt i9205 Factory data reset: Reset settings to the factory default values and delete all data.

Encrypt external SD card: Set the device to encrypt files on a memory card.
If you reset your device to the factory defaults with this setting enabled, the device will not be able to read your encrypted files. Disable this setting before resetting the
device.

or

Use this method to hard reset your Samsung Galaxy Mega GT-i9205 Android phone: Enter *2767*3855#. Warning! All your data including contacts, messages etc. will be lost! Copy all your necessary data/Contacts/Messages etc. to SIM or make backup to your PC before full reset! Take out SIM card before full reset.

General advice: Before you buy a new cell phone or new tablet, please try the following procedure to repair your device in a software way. First charge your battery, backup your important data if possible and in most cases take out SIM and SD card before doing 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.! Please also note, that a hard reset operation will not unlock your mobile phone's SIM lock or network lock, but it will remove the unlock pattern, remove the user password or PIN password (NOT the SIM card's 4 digit PIN code). Also note that the firmware version will not be affected in any way, it will not be downgraded, it will remain the same you are using and if you have rooted your device, root privileges remain also unaffected.