Yesterday we released an update for Windows Live Writer. The update primarily addresses a problem in Windows Live Writer that prevents support for posting drafts to Blogger. More information about the update is available in this knowledge base article.
This update is being distributed via Microsoft Update, so if you have chosen to have important updates automatically installed, you should receive this update automatically. If you aren't automatically getting updates, you can open Windows Update, check for updates, and the update will appear in the list of available updates.
Once the update has been successfully applied, the Windows Live Writer version number will be updated to 12.0.1367.1128, so the about dialog will look like this:
In addition, once the update has been applied, the option to post drafts to Blogger will be available and working correctly.