Newbie here - Help Required

[dnanian]

Tom -

Sorry to hear about your mistake!

While SuperDuper! certainly can create a bootable done of the drive, it seems the better thing to do until you recover your data is to use your regular OS X install discs to place a clean copy of OS x on your external drive for this purpose. Once you're all recovered, you can then use SD! to make a backup of your data, which can help in the future should this happen again...