Hard Reset HTC Desire 526+

First method:

1. Firstly, remove the battery and wait for a couple of seconds, then reinsert the battery.
2. After that press and hold Volume Down + Power button.
3. Release held keys when you see the Android images.
4. Now you should see menu of Bootloader Mode.
5. Use the Volume Down button to navigate to  "FACTORY RESET" and then hold down thePower button to confirm your choice.
6. Wait until your phone reboots.

Second method:

1. Switch on your cell phone.
2. After that from Main Menu go to Settings.
3. Choose Backup & reset and then tap Factory data reset.
4. Find Reset phone and select it.
5. Mark Erase everything and press OK to confirm the whole operation.
6. Good job! The hard rest was just performed.

WARNING !
Hard Reset will erase all of your data
All described operations you are doing at your own risk.