One major feature missing from Windows Live Writer by default is "Replace" or Find & Replace functionality. You have no ability to do a find and replace words or text with other words or text. Just about every text editor and word processor has this functionality, how can this program be lacking this crucial feature?
A search on the Internet found me a plugin by the Tech Moss Team who pointed to the Imtech Find and Replace Live Writer Plugin which functions perfectly and adds Find/Replace functionality to your Windows Live Writer installation.
Simply put, once you install the Find and Replace Live Writer plugin you will see a "Replace Text" link in your right sidebar. Clicking on this will bring up the familiar Replace window which will allow you to replace text with any other text. You can Match case and use Regular Expressions.
You can run the Find/Replace from the Edit or Source views only on Windows Live Writer and can’t run the plugin from the Preview tab.
If you are using Windows Live Writer to create blog posts and you haven’t already found the Imtech Find and Replace Live Writer Plugin, then I encourage you to download it now and add this functionality to your Windows Live Writer install.