step1. open notepad.

step2. paste this command
           java -cp bin;jars/* org.testng.TestNG testng.xml

step3. save this as filename.bat and put it inside the project directory.

step4. Now to execute the script through testng.xml , open the project and click on this bat file.

This will open the cmd and will run the entire suite.

 

Source: http://selenium-makeiteasy.blogspot.com