I have a 2006 Mac Pro that has been working great ever since I bought it used nearly a year ago, but recently I have started to get a strange problem with the ethernet. I seems randomly the ethernet will either work or wont when I boot up or come out of sleep mode, when I go into settings it says nothing is plugged in and its becoming really frustrating. I did a format and reinstall of Lion but Im still getting the issue. The onyl way I have found that seems to solve it ( or may just be coincidence ) is when I unplug the mac for an hour or so then plug it back in and boot up generally it will work ok. Anyone have any ideas what is causing this?