Just recently my home screen doesnt have a lock on it. even when i push the lock key it still doesnt have a lock code or anything. ive tried going into my setting & making a new one or even setting it, and yet nothing. Another thing is that my home key button, & my search keys are not working, they both light up when i touch them but doesnt work at all! HELP! ive tried turning off the phone & even taking out the battery! I have a Samsung Galaxy Prevail!