ipad 4 wifi, blue screen and restart!

I have an ipad 4 wi-fi and i tried to update to ios 9.1, first time an error occurred and update suddenly stopped. I tried second time and update finished with no problem, then after some hours and when i was using safari a blue screen appeared and ipad turned off, I could only start the ipad by pressing the home button and power button at the same time. Ipad worked again for one day and the same problem appeared. After using the ipad like this for a week now this problem seems to happen every hour of use. I tried to reset, restore but nothing happened. I don't know what to do and iam asking for your help. If someone know how to fix it I would appreciate to help me. Thank you!!!

yes but nothing happened!