I've got an MSI 880G-E45 motherboard and it won't start; how can I fix it?

I'm building a computer rig and I have the previously mentioned motherboard. When it's connected to the power supply the case buttons and a fan, it just doesn't start. When I turn on the power supply the internal power-button lights up, but upon pressing it or the external button nothing happens. The results are equally nonexistent with any other arrangement of components plugged in (CPU, HDD, ODD, RAM, etc). Does anyone know what's wrong or how I can fix it?