Extract (with a PortableApps folder at the device's root) and run PandoPortable.
Drag'n drop pando file in window to open pando files.
You can also drag'n drop the pando file on PandoPortable: it will launch Pando and open the file.
Don't forget to exit (right-click in systray) before shutting down Windows.
Settings of installed Pando should be preserved.