Nginx cannot open the page - linux

Question

I just build a web server using nginx and i try to change the root path but it failed. It doesnt open the page instead download a file. Also the extension of the file was not specified. Sorry for my english. Anyone can help me to fix this? here it is my sites-available/default:
# You may add here your
# server {
# ...
# }
# statements for each of your virtual hosts
server {
listen 80;
server_name localhost;
access_log /var/log/nginx/localhost.access.log;
location / {
root /var/www/rahma/wordpress;
# root /var/www/rahma;
index index.php index.html index.htm;
}
location /doc {
root /usr/share;
autoindex on;
allow 127.0.0.1;
deny all;
}
location /images {
root /usr/share;
autoindex on;
}
#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /var/www/rahma/wordpress;
# root /var/www/rahma;
}
# proxy the PHP scripts to Apache listening on 127.0.0.1:80
#
#location ~ \.php$ {
#proxy_pass http://127.0.0.1;
#}
# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
#location ~ \.php$ {
#fastcgi_pass 127.0.0.1:9000;
#fastcgi_index index.php;
#fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;
#includefastcgi_params;
#}
# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
#location ~ /\.ht {
#deny all;
#}
}
# another virtual host using mix of IP-, name-, and port-based configuration
#
#server {
#listen 8000;
#listen somename:8080;
#server_name somename alias another.alias;
#location / {
#root html;
#index index.html index.htm;
#}
#}
# HTTPS server
#
#server {
#listen 443;
#server_name localhost;
#ssl on;
#ssl_certificate cert.pem;
#ssl_certificate_key cert.key;
#ssl_session_timeout 5m;
#ssl_protocols SSLv2 SSLv3 TLSv1;
#ssl_ciphers ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP;
#ssl_prefer_server_ciphers on;
#location / {
#root html;
#index index.html index.htm;
#}
#}
Before set the root to wordpress, i just add index.php on line 'index' and create a file php.info but it doens't work too.