I've got a PowerMac G4 MDD (dual 867), slightly upgraded (2 additional hard-drives, 2gb RAM, lightscribe DVD drive) which was running 10.5.6 beautifully until this past Saturday. My girlfriend shut it down (we rarely do) during a storm and now it won't start back up! The power light turns on while pressing it but it quickly disappears. I've reset the PMU and still nothing. Any help? Thanks in advance.