please help me my iPad freezes all the tine.

O.K. so my iPad is cracked, but that can't be the reason why my screen completly freezes. I don't know why it does this. If you could tell me how to prevent this from happening or how to fix it without having to restore my iPad on the computer everytime. Yes I try the thing where you hold in the home button the while holding the sleep/wake button for 10-15 seconds that doesn't work. Oh and it's the screen that freezes though if i hold in the home button siri always pops up and i can ask her questions, but whenever I tap the screen it doesn't work.