unplugged HDMI from cable box, plugged back in no signal

My husband found our old western digital hard drive and wanted to see what we had on it, so he unplugged the HDMI cable from our xfi DVR box and plugged it into the WD and we watched a few hours of stuff, he went to unplug the HDMI from the WD & connect it back to our cable box and now it says "no cable connected" on my screen, I reconnected all cords (coaxial, HDMI, power cord) and even rebooted multiple times but it still says "no cable connected" so something went wrong when we used the HDMI cord for our WD because now it won't connect the cable to the tv, I even switched HDMI cords to see if it was the cord, but it's not it's just not signaling/connecting whatever you want to call it and showing on my screen...need help please...