Spoofing is the term being used to indicate that an email account has been compromised. Spoofing is normally caused by opening an incoming email with an attached virus. When the virus is executed, it is able to access your email credentials including User Name and Password. Once your email address has been compromised, the virus is able to send out emails through your email account as if they were being sent by you. A good indication of spoofing is when you receive emails from yourself that you know are spam in nature.
The only way to eliminate this issue is to change your email password. In certain cases, the password can only be changed by your System Administrator.
To stop or reduce the amounts of incoming unsolicited email, below are some effective courses of action: