使用.htaccess名称创建文件时遇到问题

I tried to make .htaccess file to remove index.php which I put it out of application folder but some thing strange happend my codeigniter become disable mean can not find my codeigniter in apache wamp

and when I delete .htaccess file that time only I can work with codeigniter but I want to work with out index.php

I did the following steps:

1. I went to config.php and I removed index.php

2. I create file with .htaccess name out of application folder and I put this code:

   RewriteEngine on
   RewriteCond $1 !^(index\.php|images|robots\.txt)
   RewriteRule ^(.*)$ /index.php/$1 [L]
   

result I got codeigniter become disable even if I create empty .htaccess file I can't open it even from the url and it is disappear from wamp server when I delete .htaccess that time only become normal and I can use codigniter