All, I started having a really strange issue. As of a couple days ago, I will boot my MacPro up and during the boot process it just turns its self off, then back on, then off, etc. When it turns its self off, all I have to do is bump or move the computer and it will turn its self back on (but then off again a short time later). I am thinking it has to be a loose cable someplace, but I cannot see where. I've taken the hard drives, memory riser cards and video card out and reseated them all. I've been on the phone with Applecare and they were absolutely useless. They kept wanting me to take the fans out and push buttons that were on the motherboard. When I was able to get the computer to boot (after I laid it on its side) the guy said it was fixed and closed my call out!! Does anyone have any ideas? Very frustrated.