Newbie here...Video Button Unresponsive

Hi,

I hope someone can help me out. I finally saved up enough to get an iphone (although its only a 4). Anyways I have had it about a month and when the new ios7 update came out I updated it with no problems. Now, all of sudden when I am in camera mode and tap on my video button to record something it doesnt respond at all. I have recorded thing before and it worked just fine. I have gone to the Apple store and made sure the phone is updated and I have even tried going to "Settings" and reset the phone. Still will not respond. I am late jumping on the whole iphone bandwagon I know. I hope someone out there can help me figure this out because I really love the phone. 😐