I'm trying to delete a user account. I found this page: http://docs.info.apple.com/article.html?path=Mac/10.4/en/mh1061.html
However, it won't even let me select the user account to delete it. And what is the "(-)" after "Delete" for?Deleting a user account
If you are an administrator for your computer, you can delete user accounts on your computer that are no longer needed.
When you delete a user account, you can choose to save the user's files or delete them.
IMPORTANT: If the user's account is encrypted (FileVault is turned on), turn FileVault off for the user before you delete the account.
Choose Apple menu > System Preferences and click Accounts.
If some settings are dimmed, click the lock icon and type an administrator name and password.
Select the user account you want to delete, then click Delete (-).
Click OK to save the user's files on the computer, or click Delete Immediately to remove the user account and all the user's files.
If you saved the user's files, they are stored in a disk image in the Deleted Users folder, which is in the Users folder on your Mac OS X disk. To see the saved files, double-click the disk image in the Deleted Users folder. You can drag the disk image to the Trash to delete the files.