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***THIS METHOD WILL WIPE ALL INFORMATION ON THE BLACKBERRY.***

Be sure that you have the following:

• Your Blackberry.
• Blackberry USB cable.
  
• Windows (XP/Vista/7) based machine.
• Blackberry Desktop Manager (provided by your cell carrier) installed.
• Blackberry OS (http://us.blackberry.com/support/downloads/download_sites.jsp)
  

Now you are ready.

Leave your Blackberry disconnected. Open My Computer (or Start -> Programs -> Accessories -> Windows Explorer) and navigate to C:\Program Files\Common Files\Research In Motion\ and right click on AppLoader.exe and select Run As Administrator (if you have a 64-bit OS, go to the C:\Program Files (x86)\... path).

Once you have AppLoader opened, connect your Blackberry to the USB and then plug the USB into your computer.

Watch for the screen to switch to USB-PIN:UNKNOWN. When you see it, click Next immediately. This will put the OS in reload mode. If you miss the USB-PIN:UNKNOWN, unplug, remove the battery, replace the battery, and try again.

If you downloaded an OS not Released by your Carrier, you would HAVE TO delete the vendor file (C:\Program Files\Common Files\Research In Motion\AppLoader) after installing the OS onto your PC. Otherwise, you can't upgrade/downgrade.

Once you install the OS, the vendor file will automatically "come back" in this location (C:\Program Files\Common Files\Research In Motion\AppLoader).

Now the OS will be reloaded. You can select the application(s) you want on your Blackberry and then click Next. Now the installation will start.

Once you get the The loading operation was successful screen, the phone will reboot itself. When it does, disconnect the USB cable from the phone.

The reboot will take around 15-20 minutes, be patient.

Once it boots up, you are ready to go.

Feel free to ask any questions, as I am here to assist you.