I'm new to macs and I have this looks green color imac with a front cd tray that ejects out. I have a mac os9 cd currently and I have to questions. How do I do a complete format/clean install? Like you would in windows? Because I did do some type of clean install with that disk but after 20 minutes of installing it kinda of looks like a fresh install and kind of doesnt because I still saw some prevoius folders on the desktop from the previous owner. Another question is what is the highest mac os version I can install on this imac, and how do i go about doing so? Thanks..