Hi,
Try these steps:
Firefox> Tools> Options> General> Default browser> click the "Check now"
button and select "no."
IE> Tools> Internet Options> Programs> check the box "IE should check
whether it is the default browser" The next time IE asks, answer yes.
Also (Windows XP) Control Panel> Add or remove programs> Set program access
and defaults> Working with either Microsoft or Custom, enable access to IE
and make it the default browser.
Hope this helps,
Don
[MS MVP- IE]