.htaccess file has no effect - .htaccess

Question

I have read about 10 different articles explaining how to write an .htaccess file. I've followed their explanations and put the .htaccess.txt file in the root directory. But still it won't redirect my site from non-www to www.
Here's my .htaccess file:
RewriteEngine on
RewriteCond %{HTTP_HOST} ^mecoder.co.il$ [NC]
RewriteRule ^(.*)$ http://www.mecoder.co.il/$1 [L,R=301]
<FilesMatch "\.(jpg|png)$">
Header set Cache-Control "public, max-age=321408000"
</FilesMatch>
<ifModule mod_headers.c>
ExpiresActive On
ExpiresDefault A86400
<FilesMatch "\.(ico|gif|jpg|jpeg\png|flv|pdf|swf|mov|mp3|wmv|ppt)$">
ExpiresDefault A1814400
Header append Cache-Control "public"
</FilesMatch>
<FilesMatch "\.(xml|txt|html)$">
ExpiresDefault A259200
Header append Cache-Control "proxy-revalidate"
</FilesMatch>
<FilesMatch "\.(js|css)$>
ExpiresDefault A10800
Header append Cache-Control "proxy-revalidate"
</FilesMatch>
<FilesMatch "\.(php|cgi|pl)$">
ExpiresDefault A0
Header set Cache-Control "no-store, no-cache, must revalidate, max-age=0"
Header set Pragma "no-cache"
</FilesMatch>
</IfModule>
<ifModule mod_deflate.c>
<FilesMatch "\.(js|css|html|htm|php|xml)$">
SetOutputFilter DEFLATE
</FilesMatch>
</IfModule>
<FilesMatch "\.(ico|pdf|flv|jpg|jpeg|png|gif|js|css|swf)(\.gz)?$">
Header unset ETag
FileETag None
</FilesMatch>
And here is my site

Answer 1

First, it's not .htaccess.txt but .htaccess (without .txt).
If that doesn't work, you must check if overriding with .htaccess file is enabled in your server configuration. To do that, you should add AllowOverride All to your vhost or apache configuration.