IPhone won't connect to iTunes on my laptop. For a second time?

My iPhone was already connecting to my iTunes fine whenever I plugged it into my computer. I downloaded iOS 7 and now it won't connect. I plug my phone into my laptop and my it doesn't show up underneath Devices on my sidebar. I'm pretty positive I've downloaded the most recent version of iTunes unless they came out with a new one within the last week. But yeah. I've tried everything I can think of just messing around on my phone and iTunes. Help me.

Added (1). I also have Windows 8, if that helps.

Have you let the device drivers install? What I have noticed with each release of iTunes I have to re plug in all of my devices when a new version comes out. I'm on a windows by the way. What type odf OS are you on Windows or mac? I don't know about macs though hope this is some help.