uninstalling the MySQL 5.5 0n rhel 6 (no replies)

Hi,

I am first stoping the mysql service and then uninstalling the MYSQL 5.5 on linux box with the command rpm -e --nodeps command so it's working fine.
Afetr thgis i am installing the Mysql 5.5 with rpm -ivh command it's geetin g install but
the think is it's retaining the old password even i have deleted the var/lib/mysql directory.

Please help me on this issue.Looking forward your positive response.

Regards,
Mazhar khan