Power won't turn on completely

I go to my computer and press the power button. That's strange, there is nothing happening. I press it again, maybe I didn't press it hard enough. That's very strange, it's not turning on at all. I look down into my computer and see that the green light on the motherboard is on, so why shouldn't it work. I go to the back of my computer and flick the switch. I press my power button again, still no form of power on at all. What is going on? Please help, I need my baby back.

Is the power supply on its last limbs? Is the connection to my front panel hub not connected right? Is my computer done for?
 
Back