I have contacted AOL as per the instructions which appear below, however, I have been paying Norton for years to safeguard the security of my email and the protection has obviously been inadequate. I am receiving hundreds of emails that I did not send, and many of the people in my address book are receiving them as well. Some are pornographic in nature. This is unacceptable. Please take the necessary actions to remedy this situation immediately, before I am forced to seek legal represenation and pursue my case in court: What should I do when email spoofing is done with my email address?
PerContactact service provider or your email account administrator and inform that your email address is being used for spamming. Normally, the spam filters in most of the mail servers classify those emails correctly as spams so that the recipients don't get them
It sounds like your email account has been compromised, which has allowed spammers to harvest your contacts or use your account to send spam. All of this malicious activity happens within your online email account, which is not the same thing as the email program on your computer. Your computer is not involved in any of this at all, and so security software that protects your PC cannot guard you against this sort of thing.
What you need to do is to change the account password and other means of accessing your account, such as secret questions. This will secure the account and prevent the spammers from regaining access. However, they may have your contact list, and as you say, they may be sending spam from other accounts and spoofing your address on the messages. Unfortunately, if this is the case, there would be nothing you could do to stop the activity. Usually email spoofing is short-lived though, so you can generally wait it out. The only alternative would be to change your email address.