Powermac G4 only shows desktop background
I recently acquired an old powermac G4. It was working and could connect to the internet for the person I got it from. Then when I came home and plugged it in, I heard the chime, the screen came on, and it got stuck at the background. I don't see the finder menu bar, I don't see any icons - just the swirly blue background. I have no idea how to make the icons show up. It seems like it's working, because it goes to sleep by itself and clicking the mouse wakes it back up. I just can't see any icons or programs!
Help!
PowerMac, Mac OS X (10.4.11), G4 733 mhz