Shazzam

Ok, after reading through some other posts I've tried some addition steps, removed everything, RAM, the lot, so that all that's plugged in is the power cables and the fans but still no power. CPU fan doesn't come on, nothing happens, from reading other posts I'm thinking either the power supply isn't powerful enough or the motherboard is dead? Wouldn't even a 450W power supply power at least the motherboard and processor alone though? Again any comments welcome!