Follow these steps to download and run the tool:

Download security software: Symantec W32.Esbot Free Removal Tool 1.3.0

Developer: Symantec

Download the FixEsbot.exe file.
Save the file to a convenient location, such as your Windows desktop. Close all the running programs.
If you are on a network or if you have a full-time connection to the Internet, disconnect the computer from the network and the Internet.
If you are running Windows Me or XP, turn off System Restore.
Locate the file that you just downloaded.
Double-click the FixEsbot.exe file to start the removal tool.
Click Start to begin the process, and then allow the tool to run.
Restart the computer.
Run the removal tool again to ensure that the system is clean.
If you are running Windows Me/XP, then reenable System Restore.

The Removal Tool does the following:
Terminates the associated processes
Deletes the associated files
Deletes the registry values added by the threat