Reset the device
A full reset is sometimes referred to as a hard reset. Perform a full reset when you want to clear all settings, programs and data from RAM.
Caution if you perform a full reset, your BlackBerry Curve 8900 or 8910 returns to its default settings and looses all information that is not recorded in ROM.
Before you delete your BlackBerry® device data or media card files, consider backing up these items so that you have a copy on your computer. CAUTION: If you have turned on encryption, 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 restarts after the device restarts.
To perform a hard reset:
On the Home screen or in a folder, click the Options icon.
Click Security *gt; Security Wipe.
To delete data from the messages application, contacts application, and other applications, select the Emails, Contacts, Etc check box.
To delete all third-party applications that you have added, select the User Installed Applications check box.
To delete all files from your media card, select the Media Card check box.