I've looked on Sharp's website, and for your TV model there are no firmware or software updates at all. It's not a "Smart" TV so it's not surprising there are no updates for it ---- firmware/software updates are usually only available for "Smart" models and are delivered automatically via the internet connection on the TV.
If it's scanning for channels, just let it continue until scanning is complete. If you mean it's scanning for something else, then you need to explain more thoroughly what you mean by "scanning".