Use JL_CMDER (search the forums, you'll find it right away) to wipe the handheld completely of the OS. When it's done you'll have an error on the screen that says 507. Then open Desktop Manager again and run Application Loader. It will then let you reload the OS. Leave the BB plugged in and DONT unplug it until it's done. It will appear to hang on "wait for device initialization." This is normal and can take upwards of 15 minutes with the BB just white with a spinning hourglass. Just let it go. When it's done, you should have a functioning BB again and you can restore the backup that was created the first time around.