Hmm, it could be a few things. Your power cord could be bad. I would check another one on your device (or yours on another device) and see if it works. If that doesn't do it, check the battery.
Should that not be the problem, then your motherboard may be going, but one would hope it isn't that. Start with the cord and the battery.
If that doesn't work, then you can either take it apart and check everything yourself, should you feel comfortable doing so, or take it to a local tech/repair place and have them look it over.
NOTE: Do not do anything past the cord (and battery if easily accessible only) checks if the tablet is still under warranty, otherwise you risk voiding the warranty. Should that be the case, contact the manufacturer about the issue.