Mystery Website

When I launch IE, it takes forever to open. When it finally starts there are two windows of IE active. 1 is my startup page that I setup. The other is a blank page with an IP address at the top. I know that my Norton Internet Security will block certain pages from fully loading. I have searched my system for spyware and the like, but have not been able to find anything. Does anyone know how can I find out what is causing this and keep this mystery page from loading everytime.
T.I.A.