Why am I not able to access anything apart from Whatsapp?

[Windows Central Question]

I am not able to access anything apart from wats app.

I am not able to use anything apart from wats app

start button is not working.. I can't see any app.. can not go to the main tile screen, cant use my phone book can not dial a number.. can 't see sms.. or any of my downloads.. not able to go to setting to make changes, can't even turn off my data connection.. plz help don't know what to do now? only wats app i can use... I swiched off the phone it did not work , then i tried taking the battery off but still no result... pleeeeaaze help