Thanks James, I followed your advice and tried installing using standalone.bat file. It did install the server but it gave following error while starting
The server's configuration file does not exist: F:\Eclipse EE\Server\jboss-as-7.1.1.Final\jboss-as-7.1.1.Final\standalone\configuration\Eclipse
Then I went back again and tried using the specified folder and the server started normally. I don't know why it was not starting earlier and started later on but anyways, It's working now. Thanks for help.