Intensity Shuttle 3.0 HDMI problem?

I've recently bought the Intensity Shuttle 3.0 and I've received a problem when I connect my Xbox 360 via HDMI to the Intensity input and connect it to my monitor via HDMI from the output slot and connect the 3.0 USB cord to my computer I get no video in Media Express. I've changed all the settings on my Xbox and on the Blackmagic Control Panel to 720p I still get no video. There is video from my Xbox to the monitor but no video from the capture card to the computer. I've SOMEHOW got video from the Intensity shuttle but the video was flickering. Then I lost it when I reset my computer. My motherboard is the P8Z77-V PRO from Asus if that helps. Please help me out as I really want to start making videos. Thank-You.