Norton will scan incoming email in Incredimail, Outlook, Outlook Express, Thunderbird, PocoMail, Mozilla Mail. User do not need to change anything in the SMTP or POP3 servers to make the email protection work.
Kindly ask your sister to run a scan using Housecall - http://housecall.antivirus.com/housecall/start_corp.asp and Panda ActiveScan - http://www.pandasoftware.es/activescan/activescan-com.asp
Run Spybot S&D and Ad-aware SE anti-spyware scan too.
If the result is clean, nothing to worry. Your guess is maybe right. Spoofed.
My sister is running Windows 98SE, and uses Incredimail for her emailing. She was contacted by a relative indicating that she had sent an email containing a virus from her computer. She has kept up her Norton virus detection updates, and has had no indication that she received or sent out an email with any virus. Does that version of Norton scan other email programs like Incredimail or does it only scan Outlook or Outlook express? She did run a full system scan and no virus was detected. She also ran a scan with Adware. Or can her email address somehow be spoofed? Thanks for any help.