I spent about 8 hours troubleshooting it and tried everything I could think of. No go. I checked the web and many people experienced the same problems I did: an endless on/off/on cycle.I had one give up earlier this year, or I thought it went bad. It wouldn't even POST, just a black screen. On a hunch I pulled all the cards and it fired up. It turned out I had a Firewire card that went berserk and the MB was fine.