PlayBook Power Button

The power button is at the top of the PlayBook, next to the volume buttons. I don't use the power button much. But it plays a very important role. If you need to do a hard reset, you need to press the volume +, volume -, and the power button at the same time. Or if your battery is dead and not charging for is to hold the power button for 40 seconds and then plug the charger in.

But problems have arisen for some owners. Their PB's power button is flushed or below the case. Never accept this on the PlayBook. If you bought it new return it. If buying use, inspect it before buying. You want the power button to be above the casing.

For powering off the device, there is another way. On. The home screen, there is a battery icon. Touch that icon and a menu pops down. I mostly use Stand By, as power drain should be small.

The top photo I found in a review of the BlackBerry PlayBook on AnandTech.  Below is a link to the review.  While the review is good, remember, the OS has been updated since the review and some features have been added. But still no apps.
anandtech.com