Site Search

I am looking for a plugin to "search" my blog posts.

When I looked at "Site Search" it required an install of Post Indexer.
Post Indexer does not index any previous posts.

Hence not very useful for Blogs with existing content.

Is there a work-around?
Is there a different plugin I should be looking at?

Thanks!

Notes From Post Indexer Install guide follows:
" The Post Indexer is designed to index posts from the time it is installed on your site.
The Post Indexer can’t index posts that were published prior to being installed. e,g. posts published prior to it being installed won’t display in your Recent Global posts widget"