I looked at Symantec & they said this
You are using Microsoft Outlook 98 and Norton AntiVirus 2001 (NAV) on a computer running
Windows 98. NAV did not detect Outlook 98 as an email program, so you set it up as a manually
configured email client, and you have set NAV to use a manually configured email client. After
restarting both programs, you find that Outlook 98 is not shown as a protected email program when
you click Email Status in the NAV program interface.
You can connect to your POP3 server and retrieve email, and everything else appears to be working.
You want to know whether email protection is enabled and why NAV will not show Microsoft Outlook
as a protected email program."
“This is caused by a change to the Windows registry that is made when you download and install a
Microsoft Outlook patch. At this time it only effects Microsoft Outlook 98 users.”
Which doesn’t seem to apply to Outlook 97 but you never know.