To enable ordisable InnoDB you just need to make sure if skip-innodb option is present in file /etc/my.cnf.
If it is present it means InnoDB is DISABLED and if it not present or if it is commented then InnoDB is enabled.
Thanks for the information However tell me the installation of Innodb engine and how to rename a DB with full InnoDB tables? Also I would like to know how to uninstall full innodb database tables?