I have always installed the SPx from scratch, thus my remarks to you about your routine to clean a machine before the install. Let me repeat that these three machines are homebrewed, new HDD, new PS and new RAM, all three of them.
You might have been lucky in using OEM machines, I do not know why, just a thought. I will keep you up when the time comes. In the mean time, I will be doing some fly-fishing for trout.
Be good. Oh ! Thanks for moving my previous post to a topical site. JP.