behind router...

hi i'm running xampp an at localhost it all works fine but i'm behind a router so i need to use port forwarding i guess... now my ip is 192.168.1.103 so i forwarded port 80 to it but still it doesn't work why?
https://community.apachefriends.org/f/
https://community.apachefriends.org/f/viewtopic.php?f=17&t=17401
deepsurfer wrote:do you use a Firewall ? (administrate the firewall for port 80)