This one involves a message like the following:
From: email@example.com [mailto:firstname.lastname@example.org]
Sent: Tuesday, April 27, 2010 5:36 AM
Subject: Setting for your mailbox are changed
SMTP and POP3 servers for email@example.com mailbox are changed. Please carefully read the attached instructions before updating settings.
The email has a PDF document attached. If you click on the attachment, a virus is launched and attaches to your operating system. How do you handle this type of message?
First, DO NOT click on an unsolicited attachment from an unknown source.
Second, delete the message so that you will not inadvertantly click on the attachment later.