Click on the Open Project command from the File menu. Alternatively you may click on the 
button located on the toolbar. LiqIT will prompt you to save any changes made according to the current project filename.
Open project menu command
Prompt dialog for an unsaved project
Prompt dialog for an existing project
The standard Windows dialog for opening a file will appear. Browse to the directory where the project file was previously saved, click on it and then click on the Open button.
Open project file dialog