How do I stop my email account from sending spam without my knowledge?

Scott: How do I stop my email account from sending spam without my knowledge?
Twice my email account has sent spam to everyone in my contacts list without me even being online. How do I get this to stop?

Answers and Views:

Answer by Computer Tech
For starters change your password.

Answer by Eddie Waltz
If it is web-based email, try changing your password.

If it’s being sent from Outlook or some other program on your computer, you probably have been infected with a trojan. You’ll need to use anti-virus software to assess and eliminate the infection. Be aware that if you already have anti-virus software on your system, it has probably been compromised by the virus and may not be effective.

Answer by Tony
run your virus scan
your computer is infected