Mrs Clive only has the one account on her Mac but says that her colleagues have found difficulty in removing accounts. You can delete an account but it keeps coming back again. I've found this for you on Google of it's any help.
How to delete that former user's home directory (folder)
If you have deleted a user account from your computer you know that Mac OS X wont let you delete the old users home directory folder.
If you follow these steps to delete that old user's home directory you will be very happy.
Ok, after deleting a user in the users pane of system preferences, that former user's old home directory remains on the hard disk and cannot be deleted by dragging it to the trash. The word "Deleted" is added to the name of the former user's home directory. If you try to drag this folder to the trash, an alert box appears telling you that you can not do that.
The home directory of a deleted user reverts to the ownership of the admin user. This allows the admin user to examine, move, or back up the contents of the former user's home directory before disposing of it. Once you are certain that you have moved or backed up anything that you wish to keep from the former user's home, you may follow these steps to delete the "Deleted" folder:
1. Log in to Mac OS X as an Admin user.
2. Open the Terminal utility.
3. Type: sudo rm -rf /Users/shortname\ deleted
Warning - Where the example says "shortname," you would insert theformer user's short name, which is the name (preceding "Deleted") on theHome directory you wish to delete. This step does not work if you havenot already deleted the user in the Users pane of system preferences.?Type Carefully? specifying the wrong directory path can result in dataloss, including to system files and COMPLETE death of Mac OS X
4. Press Return.
5. Type your Admin user password.
6. Press return.
The former user's home directory is now deleted. The Finder will not display this change until you log out and log back in or restart the finder.