It sounds like either something is draining the battery fast (some apps can do that), there is a bad app on the device that is messing with it and prohibiting regular use, or the battery needs replacing.
Try holding down the power button for about 20 seconds and then try charging it. If that doesn't work, but it does turn on, you should try running it in "Safe Mode" which will help you find if the problem is related to an app or other software.
To get into "Safe Mode" please do the following.
1. First turn off the tablet.
2. Next press and hold "Power" until you see the manufacturers logo on the screen, then release the power button.
3. "Quickly" press "Volume Down" and hold it for few seconds until you see the message "Safe mode...