A quote from click here with the same problem:
"the problem could be with the power supply and the monitor draining to much juice upon startup thus not allowing the computer to boot. I tried switching the monitor onto a completely separate surge protector and the computer now boots without a glitch. I have tried for the last couple of days and no problems so far. I've been able to recreate the problem by simply plugging both the computer and the monitor into the same surge protector. Don't know if this is correct but it works for now."