No user ID or Password

there is one page that has a wordpress form.

If it’s a WordPress blog it’s doable but you’ll want to read up on WordPress first.

You will need access to the MySQL database either through the command line or PHPmyadmin. Give this a good read.

http://codex.wordpress.org/Resetting_Your_Password

Make sure you get the whole works backed up first and ready to restore as a just in case.

http://codex.wordpress.org/WordPress_Backups
http://codex.wordpress.org/Backing_Up_Your_Database
http://codex.wordpress.org/Restoring_Your_Database_From_Backup

If this is too daunting then you may want to consider hiring someone.