Software Update isn't working

Turned my G4 back on after four years. Cannot eject iDisk. Also, running Tiger 10.4.11. Software Update says there is no new software for my machine. For instance, iTunes 9.0.1 asks to be upgraded, but Update takes over and says there's nothing new. Have tried removing com.apple.softwareupdate.plist to no avail. Not really Mac-savvy but willing to learn. Thanks.