tablet is not charging

My battery on my samsung galaxy 2 7.0 tablet is not charging, I tired different outlets as well as trying to charge it on my computer with the usb but the only thing that happens is the signal comes up and than the battery icon comes on goes up one level (like it's charging) and than goes back to the battery icon with the circle going around. Seems like it wants to charge but it's not getting a charge....At a loss please HELP!!!!