my iphone 4s wont display anything, can apple exchange my phone in store?

my iphone 4s screen has just completely packed itslef in and its when i press the home/unlock button, it just displays a grey screen and thats it. Ive charged it, turned it off and on again, resetted it, plugged it in to itunes but it would not show up! my iphone is out of warrenty, however if i took it into apple store, would they be able to exchange it as ive havent dropped it, it happened when i installed the lastest IOS update (6.1.3 ) and if so, how much would apple charge?

thanks guys.