11-30-2012 01:06 PM
Welcome to Support Forums
You can try this KB and see if that helps in resolving your problem.If that fails then you may have to replace your Trackball :
KB29640 : Trackpad ,trackball, or keyboard not working on a BlackBerry Smartphone.
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If Problem Resolves mark the post(s) as " Solution ", so that other can make use of it.