It doesn't boot and there is something loose floating around inside. Is there a fuse or some other component that may have become unseated?

No, but there is a breakable glass piece that it might be. Have you opened it to look and see what the rattling piece is?

By the way, with electronics, if you've got something rattling around inside, it's never a good idea to apply power until you know what's rattling. If the rattling thing is a loose screw or something similar, you can short out the electronics if it touches the wrong things.