Insignia tablet froze and won't shut off even if holding power key for 10 seconds.

Hi,
Hold down Volume Up + Power button for about 10 seconds. You ought to release held keys as soon as you see the Android Robot. To enter the Recovery Mode hold down the Power key for a few seconds. From the menu choose "Wipe Data/Factory Reset" by using Volume buttons to scroll and Power button to select options.

Perform a factory reset instrutions in back of hand book.

My grandson forgot his password for his Nextbook Tablet, how can I unlock the screen to rest his password.

whenever you forget your password you can use your google account to reset it or you send it to a technician for flashing

Press and hold the power button for 10-15 seconds. This should hard reset the tablet.

Press and hold the power button for at least twenty seconds before releasing it. Press and hold the power button for at least one second to turn it back on.

Hold the power button down for at least 10 seconds..

To hard reset a tablet, hold the power button down until it shuts off then press it to turn back on. Should take about 5 - 10 seconds for the device to power off.

if its anything like an samsung tablet hold the power button down for atlest a min. I had to hold mine down for 30 seconds to get it to reboot