how to upgrade from MySQL 5.1.30 to 5.1.49

[ravi g]

Hi, while upgrading from MySQL 5.1.30 to MySQL 5.1.49
MySQL 5.1.30 is installed with 3306 port(don't uninstall). and now just install the MySQL 5.1.49 into some other drive or directory with 3306 port(here datafiles location also is different)
what happens, it just overrides the previous installation(form the previous installation directory , all files are removed except the datafiles,hence the previous MySQL service does not work). New MySQL Instance of 5.1.49 overrides the previous instance created with MySQL 5.1.30.
new MySql5.1.49 service starts correctly, but it cannot access its own datafiles(access denied).

I think, it is better we perform uninstallation of MySQL 5.1.30 and do a fresh install of MySQL 5.1.49.

In case of MySQL 5.0 series and MySQL 5.1 Series, both installation can be done in separate directory and do not interfere with each other.

How to upgrade the minor version 5.1.30 to 5.1.49?