Can’t access individual posts

I reinstalled wordpress, after having it entirely die on me for totally unknown reasons (entire blog, including wp-admin and all files, replaced by blank screen.)

Now, the blog displays. However, I cannot view individual posts. I even wrote a new post, but it doesn’t display. Instead, it says that the post is not found, when I try to read the individual post or comment it. However, I can see the post when I look at my blog.

Thank you for any help you can give.