HELP!!!! Avast is NOT detecting a virus I KNOW that I have!!!!

I KNOW that I have some kind of email virus! Whatever it is, it’s sending emails to everyone on my contacts list and using my email addy to do it…it’s sending a link to some viagrow perv sex thing and saying it’s from me…HELP!!!

Do you use a web based mail ? I.e. Hotmail, gmaile

If so go on line and change your password