Hmm, it doesn't look like you have any other published posts, except the one titled "Blog".
Ensure you're creating new Posts by going to Posts -> Add New in the Dashboard (not Pages) and that the new posts aren't set to Draft or Private.
Otherwise, you might try deactivating any plugins to rule out a conflict.
Try deleting/reinstalling the theme to ensure nothing was corrupted during installation.
Activate one of the default themes (Twenty Twelve or Twenty Eleven) -- do your new Posts appear with those themes? If not, it's probably an issue with your WP installation.