So i've noticed that when i get a new text it doesn't always notify me with a sound that i've received one. It'll light up and vibrate but not make any sound. why is this? Oh and can i turn off text message previews?
As far as getting your sound back. Hold down the home button and sleep button together until you see the Apple logo. When the phone reboots you should be fine. This is providing that you have a sound chosen in the sounds menue. You might want to check that first. Version 2.0 and above has had a mind of it's own in regard to messing with settings.