sign into icloud box won't go away

As soon as I power on my ipad mini, the sign into iCloud dialogue box pops up. I type in the password, but it pops up with the box again as if I didn't type anything in. I've tried holding the home and power buttons simultaneously to restart it, to no avail. Box comes back once it reboots. I've tried to restore to factory settings from itunes, but the ipad wants me to turn off the "find my ipad" option in the settings. I can't do this either since the ipad won't let me connect to wifi/internet to verify the password for my apple ID.