The project default directory is
\Borland\Delphi 3.0\Bin,which annoys me regularly.
This setting can be changed via right-click on the Delphi program icon:
"Properties" -> page "Shortcut", field "Start in:"
(German version: "Eigenschaften" -> "Verknüpfung" -> "Arbeitsverzeichnis").
Here you may enter your default - project directory.