by Hard Reset
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.!
BlackBerry 8500 hard reset
Delete all device data
Verify that you have a backup copy of your BlackBerry® 8520 device data.
CAUTION: If you have turned on content protection, the process for deleting all device data can take up to an hour to complete. You
cannot stop the process after you start it. If you reset your device, the process continues after the device restarts.
1. In the device options, click Security Options.
2. Click General Settings Security wipe.
3. Press the Menu key.
4. Click Wipe Handheld.
5. To delete all third-party applications from your device, select the Include third-party applications check box.
6. Click Continue.
7. Type blackberry and OK.