Well it could be a few things. Have you tried charging it? And if so, does it say it is charging? Or does it not show anything at all, even when plugged in to charge? If the last one is the case, then it could be the charger cord is not working correctly, so you would need to try a different cord on the device. Or it could be that the battery is no longer holding a charge and needs replacing.
Now if the tablet is still under warranty, you should contact the manufacturer about a repair or replacement. As to work on it yourself (or get someone else to) would void the warranty. However, if it is no longer under warranty, then you are free to have anyone you want do the work.