my iPad won't let me put in my password
First it would not let me put in a password. Then I tried to power off and I got a white screen. Now nothing but the white screen.
iPad (4th gen) Wi-Fi, iOS 8.1.1
Try a device reset. If that doesn't help, you should take your device to an Apple Store for a free evaluation.
Device Reset (won't affect settings/data/music/apps/etc)
1. Press and hold (& continue to hold) BOTH the Sleep/Wake button & the Home button.
2. Continue to hold BOTH (ignoring any other messages that may show) until you see the Apple logo on the screen.
3. Release BOTH buttons when you see the Apple logo and allow the device to boot normally.