Virus sending 100's of emails that I can't find

Hello Richard,
I understand how something like this can really try your patience. Could you please let us know how come you came to a conclusion that you have virus in your outbound email? if possible please provide us the screenshot http://avgread.me/1aZxsAV of the issue to assist you better.
Please feel free to contact us for any further assistance. Thank you.

My outbound email using Verizon's SMTP was suspended because of abnormal activity of 100's of emails being sent. 

I don't know how these malicious programs use my smtp settings to send email as i don't see anything in my outbox of Outlook.  

I've done a full scan with my AVG Internet Security version 2015.0.6176 but it didn't find anything.

How do I find and fix the problem?   Thanks.

Hello Richard,
I understand how something like this can really try your patience. Could you please let us know how come you came to a conclusion that you have virus in your outbound email? if possible please provide us the screenshot http://avgread.me/1aZxsAV of the issue to assist you better.
Please feel free to contact us for any further assistance. Thank you.