Might be a long shot, but I had to put a new serial board in a pc and when I did so, it would not connect with the mill. I'm using a different mill and software, but sounds like a similar problem. The answer was to slow down the baud rate in my milling software. The mill was "older" and the serial card was the latest and there was just enough of a difference that they would not connect. I still have to keep flippng online and offline, sometimes half a dozen times, when I boot up, but once I have it, I'm good until I shut down again. I have since been told that some brands have better communications than others and this is not an uncommon problem. Before doing anything drastic, I would ONCE AGAIN replace the cable--sometimes they do go bad.