This is just strange, and I'm struggling to get my head around it! My partner has been using my old iPhone 4S since I got a 5 at launch, and it's been fine other than replacing a cracked screen. A couple of weeks ago she was complaining that she couldn't hear a video I'd added to a shared iCloud but I didn't think anything of it. She was trying to show me another video she'd taken last weekend, and it played without any sound. I've spent a little time fiddling with it, and whilst it's fine for making calls and for some app sounds, I don't get any sound from the Music app or for any video. It plays through the headphone jack, but nothing from the speaker. I also noticed that when the headphones are plugged in, using the volume buttons brings up a volume bar, but when the headphones are unplugged the volume buttons don't do anything anymore. I've done some googling, and some threads seem to suggest a problem with the dock connector and the phone thinking it's docked, but not seemed to have a solution. The phone charges OK through the dock, and syncs with iTunes. I'll probably upgrade to a 6 in a month or two so she can have my 5, but would be good to try and get the 4S working again as a backup. Help!