Microsoft really needs to TEST all Registry cleaners & make a list of the Top 5 BEST software for many different uses and post that list so your Customers can know what is the Best to use to Fix their PC problems .
Microsoft does not recommend using a registry cleaner.
Slow PC? Optimize your computer for peak performance:
http://www.microsoft.com/athome/setup/optimize.aspx
"Note: This article does not address or recommend tinkering with the registry files. Such activities can be detrimental to your computer and should only be attempted by properly trained professionals."