eman, the most common reason for that is because the battery is completely drained out, discharged below the charging threshold. The problem with the playbook is that it will not charge, if it is drained past that point. Try these solutions:" Solution: try these 3 different step by step solutions. Hopefully one of these wille work for you.

1. Press the Power button and you should see the Playbook Logo ( chances for this are low )

2. Press the power button and the volume together, if there is 1 % charge left, there is a chance that it will boot up. When you see the logo, immediately charge the playbook.

3. This solution requires patience. Plug the charger into the socket and plug the USB into the playbook. The red light should stay on for 8-10 secs. Remove the USB cable from the playbook wait for 2 to 5 sec and plug the USB cable back to the charger and wait till that red light comes and goes again. Repeat this step at least 20-30 times. The only power that the playbook gets, is when that red light is on when plugging the USB cord into the playbook, once that light goes off the playbook is not charging.. so what you are doing here is forcing the playbook to get charged for 8 sec every time you plug it into the playbook. This way the playbook gets enough power needed to boot. Once the Playbook has enough power to boot, the red light stays and changes to green but this time it should be blinking slowly slowly and keep on blinking. You should also see the playbook logo return. The green light keeps blinking until there is enough charge for the playbook to stand on its own, then changes to a solid red until it gets fully charged." from here. Just remember to do this often, and that it will require lots of patience. You should also consider to use an AC wall charger since they supply a higher amperage than a USB port. Hope this helps, good luck.