How to remove other admin account on OS X Lion
I bought a new MacBook Pro 15", updated with OS X Lion, then migrated data through Migration Assistant from a Time Machine Backup. This created a new user account. I just want to delete the initial account created when I first initialized my computer, but it doesn't work, using the normal method. Opening Users & Groups on the System Preferences menu leaves both admin accounts greyed, so they can't be selected. Any help regarding this issue?
MacBook Pro, Mac OS X (10.7)