Move Acquia dev destop sites to another local enviroment
(Just saw your comment that you are not using Acquia Cloud so I'm editing my answer.)


Copy the current location of your local sites to your new computer.
Download the latest version of Dev Desktop.
Click on the plus sign at the lower left side of the Acquia Dev Desktop window and select Import local drupal site. In the following dialog, select Change... in the top right corner and select the root folder of your site.


FWIW: The default location of dev-desktop sites is:


  ~/Sites/devdesktop/(site root folder)


You may want to keep this convention for convenience/clarity's sake

I seem to remember having to import my sites individually after upgrading my Acquia Dev Desktop. As you can see from the above, it's really easy.