After moving wordpress to a new server , I used the same domain in the old server , it's display "Nothing Found" in the index page , and even can't get the posts in "The most comments" widget , and even in the Admin panel i can't see it but I can see the posts counter (15,000) post , but i can see the posts in wp-posts table .
Multiple things could be going wrong here,if you give some more infomation I can give you better answers here are some things to try.
Check the wp-config.php to make sure the correct database settings are being used
If you had permalinks you may want to check for or recheck the .htaccess file
can you login via example.com/wp-login.php?