-Connect your blackberry to your computer and make sure you are running the latest blackberry OS as well as desktop version.
-Open up a command prompt (start...run... type "cmd"...enter) and type "cd c:\Program Files\Common Files\Research In Motion\AppLoader" then hit enter.
-verify that you are in that directory and type: "loader.exe/resettofactory" and hit enter
This will wipe the device.