kingsalamander, welcome on Gnutella forums.

Very strange.
Do you have, by mistake, rename your home folder, you know the name of the little 'Home' icon you see on the left pane of a Finder window ?
Do you made a search with the name of the .dmg you've apparently downloaded to see where this file is located (normally, the file is downloaded in the folder you have specified within LW preferences) ?

Installers package (eventually included in .dmg files) requires a password for installing, so I do not believe the .dmg 'has done something' by itself.
Regards
Philippe