1. please click on WAMP icon select Apache -> Service -> Test Port 80 // this will check if the port is used by any other program
  2. Also do this select Apache -> Service -> Install Service // this will make apache use port 80 if already not used by any other program like IIS or Skype.

If port 80 is already used by some program, then you need to change the listening port for WAMP. To do this –

click WAMP icon -> Apache -> httpd.conf

Now find listen 80 or something like that

WAMP server uses the Port No 80 (HTTP default port),some times other services might be using port 80 and dont allow the wamp server to use it.
You need to change the port no 80 to others like “81/8080/8081” from (wamp server icon- Apache-httpd.conf file).
Restart services and run the wamp server.