I'm not sure if this is actually possible, not without a plugin anyway!
You could use an auto-indentation plugin like the following: http://sourceforge.net/apps/mediawiki/notepad-plus/index.php?title=Plugin_Central
A quick way to adjust indentation as well is to highlight the whole misaligned section and press Tab to move it all to the right, and press Shift + Tab if you want it all to move to the left!