Make sure you download and install the Desktop Manager, preferably Version 4.2.2. Then download and install the BB Operatiing Software, this is the software that is currently on your BB. Then open up the Desktop Manager, (DM) hit Application Manager to see if the software needs to be updated, do not attempt to install anything at this point. After this process, could take up to 20 minutes, the BB will re-boot and you should be good to go.
BlackBerry Operating System Downloads - BlackBerryFAQ
BlackBerry - BlackBerry Desktop and Device Software Download Sites