Hide individual public pages from WordPress search, such as confirmation and download pages that should only be accessible via a squeeze page.
If you don't meet the below requirements, I highly recommend you upgrade your WordPress install or move to a web host that supports a more recent version of PHP.
/wp-content/plugins/directory and unzip
Once the plugin is installed and activated, go to a post you want to hide and check the 'Hide from search' checkbox on the bottom right of the screen and save your changes. Viola! The post has been hidden!