Display two HTML pages in IE 7

Hi,
I am using the .net WebBrowser control to display two html pages. The
webbrowser controls navigate call looks like this

Webbrowser.navigate("http://localhost:1025/First.html:Second.html");

Both the HTML pages are displayed correctly one below the other in IE
6.

However after installing IE 7, only the first html page is displayed.
I have debugged and found that all the request , data sent is the same
for both IE 6 and IE 7.

Can anyone please tell me whats wrong with IE 7 that after installing
it two htmls are not displayed, only one is displayed?

Thanks for your time,
Regards,
Amol Kakhandki.