IPhone 4s screen went black. The phone is still on. What do I do?

I was on instagram and my iphone screen froze. Then it turned black. The phone is still on. If i hold the home button i hear siri and i hear messages coming in. I can't connect my phone to my laptop because my laptop is too old for the new version of itunes to work (thats what it always says when i plug in my phone) is there any way to fix this without using the computer? Or do i have to take it to the apple store or verizon?

On my iPod 4 I just let the battery die and then it worked when it came back on. I don't know if that will work with an iPhone 4S but you could try!