My site became corrupted with malware yesterday so my site was taken down. I had to delete all my site's files. I had backed up my WordPress directory so I uploaded it back to the site today. When I visit my site, the front page looks fine, but when I click on a link to a post or a page I get a 404 error page. I'm thinking that this might have something to do with the database and the site files. Is there something that I need to do?