Wecome to justanswer
As you have already tried replacing the battery, so next step would be to clean the cover for any strain clogged in the mechanism.
Find a hand-powered air blaster (also known as a hand cannon). Blow the air into the lens.
If there is any dust, it will be cleared by this method.
If you can access your camera's menu, try finding the "factory reset" option to return your camera to the factory state. If there are any errors in the settings then it might get cleared by this step.
If blowing compressed air didn't help remove sand particles from between the lenses, you can try using a piece of paper to get the sand particles out. Use the paper between the inner and the outer lens and on the outside of the outer lens. Don't insert the paper too deep, you could accidentally dislodge some of the components. We recommend you don't go in more than 1cm.
Nathan, reset to default settings failed. Will get air cannon and try that sometime. Have ok'd service but can't rate higher as no result so far.
Okay, take your time and revert back after trying the above specified cleaning methods.
Nathan, will find a hand-powered air blaster sometime. Default reset failed. Have rated OK but not higher as not fixed yet. Cheers, Bob