Why did power button collapse in?

Shut it down by simultaneously:

Holding down power button
Holding down volume down
Holding down Home button

For 10 seconds.

After shut down, restart it.

In this case Kindle technician might be help you Just give them a call Kindle Technical Support Registration 877 690 9305

Here are two things to try:
I- Using the Power button:
1 Press and hold the Power button for at least 4 seconds.
2 Swipe-down the shutdown confirmation screen to the bottom
edge of the display to turn off the tablet.
Using Charms:
1 Swipe-in from the right edge of the display to access Charms.
2 Touch Settings
Turning Off the Screen
Using the Power button:
Press the Power button to turn off the screen.
Using Charms:
1 Swipe-in from the right edge of the display to access Charms.
2 Touch Settings
NOTE: If your tablet is in a standby state (tablet is on, but screen is off), press the Power button or Windows button once to turn on the screen.
12
'
Setting Up Your Tablet
? Power
? Shut down to turn off the tablet.

II- Unplug the battery, wait 30 seconds, then install the battery again.

Rebooting is easy. It is called a hard reboot. Just hold both buttons down until you see a red slider, and then slide it to shut down. It will restart, and you will see the Apple logo.

Press and hold the power button for fifteen seconds or so, ignoring the shut-down prompt, until it shuts off. Release, then press and hold the power button for a second or two until it starts to reboot.

The problem could be that you are pressing down the power button and the volume button at the same time when you shut down. That will cause an android tablet to reset itself. There may be an issue with the power shut off button.

Press and hold the power button for fifteen seconds or so. If it prompts whether you want to shut down, ignore it and keep the power button pressed until it shuts off. Release the button, then press and hold for a second or two until it starts to reboot. Does it reboot and operate normally now?

So you need to be In the main menu interface then press the power button for about 5 seconds to shut it down. Below is the power section out of the manual.


1.2 POWER
startup: Long Press and hold the power button, the system will enter the main interface
shutdown: In the main menu interface, Press the power button about 5 second to shutdown, The system can hint "power off" option, Clike"ok". you can safely shut down.
Lock screen: Short press Power button to lock screen or unlock screen.
Remark 1.When power is empty,system will shut down automatically.
2.Illegal turn off the device,restart will scan and restore the disk,it may take longer time to enter into system

Press and hold the power button for twenty seconds, ignoring the "Shut down" prompt until the Kindle shuts down. Press and hold the power button for a couple of seconds until it starts to reboot.

Press and hold the power button for fifteen seconds. Does it shut off then? If so, press and hold the power button for two seconds until it starts rebooting.