Here’s a way to change PowerPoint 2007 default slide layout without the inconvenience of altering or creating a PowerPoint slide master or installing an add-in.

1/ Open a new PowerPoint blank presentation.

2/ Right-click on your slide and select the desired layout.

3/ Save your slide as a PowerPoint Template (“Save as type” drop-down menu in Window Save Dialog Box) to MS Office default templates directory (C:\Documents and Settings\user name\Application Data\Microsoft\Templates)  or to a location of your choice.

4/ Create a shortcut to your template (could be placed in Window Start Menu for instance) and use this to launch PowerPoint which should now open with your default layout.

 Note that choosing “New” from the Office Button (Ctrl N) will open the PowerPoint original layout. In order to avoid this so you’ll need to use the shortcut to your template to create a new PowerPoint document instead.