Press and hold the mouse or trackpad button down when you power it on and keep holding it down. This forces a disk eject, or at least tells the mechanism to to go through its eject cycle. This may move the mechanism to it's fully open position for you.
The superdrive CD ROM/DVD drive won't spin if there is no disk in it, you probably hear the hard disk drive spin up. It's the motherboard alright. Can be replaced (costly) or repaired by an expert who is familiar with these. Some Dells (Latitude D630) do the exact same thing but startup, just with whacked out video or none at all, internal or external. Macs check (at startup) memory and other vitals and you don't get the startup chime if all isn't well. PCs don't do anywhere near as thorough pre-flight check so they startup but are still perfectly unusable.
Hello Art, When you power it on there is no startup chime, correct? There's no backlight on the display, correct? The sleep indicator on front comes on by not full brightness, correct? It powers down again if you press and hold the power button for several seconds, correct? When on if you press the uppermost left and uppermost right keys on the keyboard together the sleep light dims, correct? If I'm right so far, remove the battery, unplug the AC adapter from the laptop. Press and hold the power button down with your right hand while you reconnect the AC adapter plug. It should come on with the fans running at the highest speed and the sleep light is now off. Press the power button down and hold it until it shuts down. If it does what I have written then the motherboard needs to be repaired. I repair these. If interested email me. Don't let a good Mac go bad and stay that way. It's an awesome feeling to bring them back to life. I like to quote Dr. Frankenstein by saying, "It's alive! It's alive!"