Tablet Powers On But does not show home screen!

Hello Friends,

I have a Lenovo Tab. This tab turns on when I press power on button but the screen always shows a white circular buffering icon with a black background and remains the same. When i pull down the top notification bar, it pops up and shows icon of wifi, bluetooth , data ,etc but the tab's home page does not start and I can do nothing about it. I tried doing factory format option on recovery mode but still the same thing happens. Please help someone!