Okay, so my computer is a 2.1 ghz core 2 duo white plastic macbook. It is currently running with a standard apple combo drive. I'm trying to install windows via boot camp, but the only version I have of windows is an upgrade version - which means that half way through the installation I need to REMOVE THE INSTALL DISC and replace it with an OLDER VERSION OF WINDOWS. So, how can I force my machine to eject the Disc without shutting it down?