If you pressed the "turn on" switch, which is located above the right of the screen, try pressing it again. Hold it for a second and then let go.
If that doesn't work, check the battery. Chances are that the battery may have to be charged. Plug it into the charging station. It may not turn on right away if the battery is completely empty, but you will be able to tell that it's working if you see lights come on once you plug the device into the charger. If there are no lights, chances are that the battery is bad. The battery may have to be replaced. To do that, the device will have to be taken apart.
If you tried everything and the device is still not working, then it may be the motherboard that will have to be replaced.
If the front buttons are broken or stuck then they may not be sending signals to the motherboard. To fix the problem, the device will have to be taken apart.
If the buttons are not the problem, then it may be the motherboard altogether, which will have to be replaced.
If the screen is blank, the screen might be bad.
If the screen is blank, the device may have to be charged. However, if no lights come on while charging it may be the battery that will have to be replaced.
Check the power button. The power button may be stuck.
If the power button appears to be in good working condition, the battery may be dead. Try to charge the device. If the device still fails you might have to replace the battery all together. The battery is replaced by removing the back cover of the device.
Check the volume button. The volume button may be stuck. If the volume button does not fix the problem, turn the device off and back on. If there is still no sound, the speaker may have to be replaced.