How to stop my computer from beeing a spam emailing machine??

Hi, I am using Windows XP Pro SP2.

For several days my computer has been used as a spamming email machine, how do I know that?

I know because I was using Norton antivirus with it's email scanning capability active!

Suddenly my laptop's desktop started to get flooded with many many small windows from Norton's email scanning module that were showing where the email was beeing sent, it's title (that's how I know that they were sending out spam advertising) and also that it is being scanned/rejected/unable to be sent!

My computer gets overload so I had to deactivate email spamming! But my computer kept being very very busy. I unistalled Norton and tried AVG and NOD32. I think the last one did something but I am not sure if the problem is solved!I always check windows task manager and the local area connection status window to show any "redundant acticities".

How can I be protected from this once and for all?

I try to avoid heavy programs such as Norton and Mcfee!!

Thank you people.

How to stop my computer from beeing a spam emailing machine??liveupdate

FTC Consumer Alert

Federal Trade Commission 鈻?Bureau of Consumer Protection 鈻?Office of Consumer and Business Education

Who鈥檚 Spamming Who? Could it be You?

Spammers may be using your computer to send unsolicited 鈥?and possibly offensive 鈥?email