How to uninstall a program from its root?

[boRn-cOnFuseD]

Hi, guys I just wanted to know how to uninstall a program from its root. Like saying when you normally uninstall a program and after sometime when you install it back it has the same settings or stuff you changed in the first time. So, just wanna know how do you stop that from happening?

 

[rgd1101]

use ccleaner