Computer trouble

My class just bought a computer for a project. It has an Asus server motherboard, 2 AMD Opteron dual core processors and 4GB of ram. We connected everything properly and everything is running, but the boot screen dosent come up. We replaced the motherboard thinking it was bad… same thing. We replaced the monitor, and hard drive, and changed the ram around… no luck. we even removed one of the cpu’s. plz help (its for a mineral oil computer, but we are trying it out before we put it into the oil.)