you most likey have a defetive part then.. if you have no way of testing each piece individually.. then i suggest taking it to a computer store and have them test it for you.. they'll charge you.. but i don't think you have any choice.
Try just using one stick of ram in single channel. I know that some DFI Ultra-D and SLI boards don't play nice in dual channel with some types of ram. It's a long shot seeing as you have an Asus board, but it couldn't hurt.