You will require Selenium RC which you can download from the below link:
Also, download Java 1.7 or above and follow the below steps:
1) Install Java
2) Setup Selenium RC.
3) Open cmd.exe window and go to the directory having the Selenium Server (selenium-remote-control-1.0.1\selenium-server-1.0.1)
4) Run the command as shown below:
java -jar selenium-server.jar -htmlSuite "*firefox" "http://10.8.100.106" "C:\test.html" "C:\testresults.html"
This will run your test script in Firefox and write the results in the HTML file. However, You will need to change the "http://10.8.100.106" argument to your own server ( localhost / 127.0.0.0)