I have both Mac OS 9 (Classic) and OS X running on my eMac - it was like this when I bought it! However, the OS 9 is now preventing me from installing my new printer, and I've previously been told that I shouldn't have it running any way. Does anyone know how to get rid of the OS 9??!! The fact that it's just installed on the computer and not running is still stopping me from adding the printer.

Having Classic (OS9) installed should NOT stop you from installing anything. Any installer that complains about Classic being installed.. Classic is in no way referenced by OS X until it's actually started, so an installer should not care about it's existence. I'd very much like to see a screen shot of the installer complaining about Classic being installed.

If you are sure you never need it (do you ever run Classic?), simply remove "System Folder" and "Applications (Mac OS 9)" from the root of your hard drive. Please note, there is also a folder named "System", do NOT remove that. It's part of OS X.