I can read plain text emails but can't read HTML in Outlook 2003

I've cannot read most of the emails (body only) that come to me. I see the
headers fine. I've determined these are in HTML format. I've tried turning
on and off Norton Antivirus - does not help.

Recently I tried sending emails to myself in plain, rich and HTML formats.
On the send everything is fine. When I go to Comcast web site to view, I can
see each of the 3 email bodies - everything is normal. When I turn on my
Outlook 2003 to get emails (on my home computer), I can only ever see the
body of message sent (from my computer) in Plain text. The body sent in rish
and HTML shows blank.
Help