Dave-So; Did you load your P5 with the DVD-CD unit? I went through a period of -hellish- instability, and it proved out to be that type of drive. It was somehow corrupting installs; the best I could determine was it was either a physical misalignment, or there was a firmware glitch and it was losing track of what compression scheme it was supposed to be reading. And it always seemed to be most prevalent with the installers like VISE.