You don't happen to have a Northwood CPU that you are overclocking, do you? Because I had the same problem. When I first did the wire mod trick, I didn't do it correctly so I didn't get a higher default vcore. When I corrected the mistake, my vcore was now high enough to boot up the system. If you have a Northwood, try performing the wire mod to get a higher default vcore. If you aren't, then ignore what I just said. 🙂