Problem: Clicking an email hyperlink on a website, causes multiple pages to spawn and displays the message "default mail client not installed properly"

Solution:
1. Go Start > Run and type:
"C:\Program Files\Outlook Express\msimn.exe" /reg

2. Open Internet Explorer > Tools > Internet Options > Programs
then set Outlook Express as default email handler.

If it doesn't appear in the list, this free tool can restore it there...
http://www.dougknox.com/xp/scripts_desc/oe_client.htm