My iPhone 4S won't let me slide to unlock or answer but touchscreen isn't broken.

Hello, I tried using my IPhone today and it just stopped letting me slide to unlock, it was working fine earlier but now it won't respond. I know my touchscreen isn't broken as I have to use the assistive touch (My lock button is broken) and that moves fine anywhere on the screen, I can also pull the notification bar down and the other bar up but it won't let me ineract with anything on them. I have tried getting a friend to call me to see if it will let me answer my phone but I can't do that either. I can't turn my phone off even using the assisitive touch as I will still have to slide the bar and I am unable to do that, I can't reset the phone and my laptop is broken so I can't connect my phone to Itunes to see if that makes a difference. It also isn't connecting to my home wifi therefore I am also unable to use Siri!

So does anyone know if it will work if I just wait fot the battery to run out then plug it back in to switch it on? Or does anyone have any other ideas of what I can do without having to take it into store, as a student I can't afford to pay for anything and it isn't under any insurance or guarantee.

Thank you!