How to Remove Eject Button from Finder

The first thing to try in these cases is to restart the computer and hold down your Eject key or Mouse/trackpad button while it's starting up.

If that doesn't work, try Resetting the SMC on an Intel based mac, or a PMU reset on an older PowerPC machine, then try again.

If that fails, you'll want to bring the machine into an  Authorized Service Center if it's under warranty, or look into less orthodox solutions if not.

If this behavior persists past a reboot, you might need to go down some general problem isolation steps:

• Isolating issues in Mac OS X

There used to be an article (it's gone or I can't find it at the moment) that walked you through setting aside the application preferences or testing this behavior in a new user. In your case - it looks like you figured it out, but I wanted to at least mention the official guide in case others have the same symptoms but a different cause.