Quick question to all...This might sound stupid, but it did affect me. Is the cable fimly plugged into the HD. I mean, no gap where the pins on the HD connector is visible. I had this issue myself, and the replacment cable I got didn't change anything, but when I pushed that connector all the way down so there was no gap, I've not had a failed boot. (searches for wood to knock on) but YMMV.