When you are going to browse your web service or WCF Service, you can get this error “Serviec Unavailable”.
This error may occur if the password of Application pool assigned to Web Service or WCF Service is not correct. So to resolve this one you need to change it. You can change it using the IIS Services.
To change the password of application pool, see the properties of the application pool using IIS Services. and change the password. Restart the IIS using IISReset in Start=>Run.
Test your Web Service or WCF Service, it will work.