I don't quite understand what you are asking. If you go to your Applications folder>System Preferences>Users & Groups>there look in the left hand column at the list of "User Names" (Accounts) that currently exist on the Mac. Yours has to be one of those. If Your previous User Name is NOT found there, then that Account has been fully Deleted and all the data and apps associated directly with it are gone.
i went into system preferences and i wanted to disable the buest account. But i changed the login type to username and password. when i restarted the mac i do not remember the username for my account. i know the password but the username is wrong. is there anyway i can either find out my username or change it without having the installation disk?