Url Manager

Hi, can i know why my application is not working if i removed comments in urlmanger from config/main.php. One of my application needs to remove comments to urlmanager, but, when i remove comments the it saying like this…

Not Found

The requested URL /personalTrainer/site/login was not found on this server.

     How to solve this error.

It could depends on your .htaccess file, virtualhost, …, and value of showScriptName in yii configuration file.

     Where i need to change in .htaccess file?