Microsoft IE 6, Microsoft XP Professional, Word 2003, Outlook 2003

I need to provide security for emails sent from my computer to another
individual. I am concerned because a known hacker still has access to the
recipient's computer after installing a key tracker and hijacking the
recipients email account to send emails under the recipients email address.
(that was taken care of with spybot and other means)

Now, I found out that the hacker has been checking the History on the
recipient's computer. What else the hacker might be up to is anyone's guess.
I am not sure if encryption will help, but would like to find out if it
works.

After reading the HELP for encryption and certificates, I still do not
understand how to encrypt emails.

Does anyone know where there are good lessons on the subject, with online of
in any other resouce, such as books?

Aprreciate your help.