TuneUp Utilities 2007 is being offered completely free.  It's certified for Windows Vista by Microsoft and works with previous versions of Windows too.  Here is a review.  Per the instructions on the page:
You need a serial code to use TuneUp Utilities 2007. Enter code JMNCG-FKNGR-WMAMT-FRTQL-BLYJB-XDYMX with your name to register the software. Note that Incisive Media are authorized to provide this full commercial software…