Open Dialup Networking by double clicking on the 'My Computer' icon from your desktop.
In the Dialup Networking folder you will see all your ISP connections including your Freeserve connection.
You can remove the Freeserve dialup networking connection by simply deleting it - click on it once with your mouse, then press the delete key on your keyboard.
If you've been using Freeserve as your default ISP, you may need to follow further instructions to set Internet Explorer and Outlook Express to use different internet connections once you remove the Freeserve connection.