I am not sure how many times this question has been answered before, but every answer that I look at gives a different approach to solving this problem of which none of them worked. I am migrating from Apache to Nginx and am facing some serious problems with setting it up. My /etc/nginx/sites-available/default looks like this...

# You may add here your
# server {
# ...
# }
# statements for each of your virtual hosts to this file

##
# You should look at the following URL's in order to grasp a solid understanding
# of Nginx configuration files in order to fully unleash the power of Nginx.
# http://wiki.nginx.org/Pitfalls
# http://wiki.nginx.org/QuickStart
# http://wiki.nginx.org/Configuration
#
# Generally, you will want to move this file somewhere, and start with a clean
# file but keep thi;s around for reference. Or just disable in sites-enabled.
#
# Please see /usr/share/doc/nginx-doc/examples/ for more detailed examples.
##

server {
#listen 80; ## listen for ipv4; this line is default and implied
#listen [::]:80 default ipv6only=on; ## listen for ipv6

root /usr/share/nginx/www/flo2go/;
index index.php index.html index.htm;
if ($request_filename !~ (js|css|images|robots\.txt|index\.php.*) ) {
rewrite ^/(.*)$ /index.php/$1 last;
}

# Make site accessible from http://localhost/
server_name localhost;

location / {
# First attempt to serve request as file, then
# as directory, then fall back to index.html

try_files $uri $uri/ /index.php;
# Uncomment to enable naxsi on this location
# include /etc/nginx/naxsi.rules
}
location ~ /index.php/
{
include /etc/nginx/fastcgi_params;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME /usr/share/nginx/www/flo2go/index.php;
fastcgi_param REQUEST_URI $request_uri;
fastcgi_param QUERY_STRING $query_string;
fastcgi_param REQUEST_METHOD $request_method;
fastcgi_param CONTENT_TYPE $content_type;
fastcgi_param CONTENT_LENGTH $content_length;
fastcgi_pass unix:/var/run/php5-fpm.sock;
}
location /doc/ {
alias /usr/share/doc/;
autoindex on;
allow 127.0.0.1;
deny all;
}

# Only for nginx-naxsi : process denied requests
#location /RequestDenied {
# For example, return an error code
#return 418;
#}

#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 /usr/share/nginx/www;
#}

# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
location ~ \.php$ {
fastcgi_split_path_info ^(.+\.php)(/.+)$;
# # NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini
#
# # With php5-cgi alone:
# fastcgi_pass 127.0.0.1:9000;
# # With php5-fpm:
fastcgi_pass unix:/var/run/php5-fpm.sock;
fastcgi_index index.php;
include fastcgi_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;
# root html;
# index index.html index.htm;
#
# location / {
# try_files $uri $uri/ /index.html;
# }
#}


# HTTPS server
#
#server {
# listen 443;
# server_name localhost;
#
# root html;
# index index.html index.htm;
#
# ssl on;
# ssl_certificate cert.pem;
# ssl_certificate_key cert.key;
#
# ssl_session_timeout 5m;
#
# ssl_protocols SSLv3 TLSv1;
# ssl_ciphers ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv3:+EXP;
# ssl_prefer_server_ciphers on;
#
# location / {
# try_files $uri $uri/ /index.html;
# }
#}

I have tried everything to make my web application work. All I keep getting is the 404:Page Not Found error. The site was working perfectly on Apache and after spending almost 3-4 hours in solving this problem I thought that it would be better to seek the advise of experts on this forum. Hope somebody can bail me out of this situation :(