If you want a quick and dirty way to completely erase your Blackberry
1. Connect the BlackBerry smartphone to the PC computer.
2. Open a command prompt on the PC (I suggest with admin privileges)
3. From with the command prompt CD to C:\Program Files\Common Files\Research In Motion\Apploader or C:\Program Files (x86)\Common Files\Research In Motion\Apploader
4. Type loader.exe /resettofactory
After a few minutes, all data and settings should vanish from the device