IE7 wont let me sign in!!!!!!

[midium]

When i boot up my pc Windows live messenger signs in immediatley and connects fine,Firefox that i use all the time works fine when i log into my hotmail account but IE7 states that i have no connection. It'll tell me that i have no connection when signing in then i can hit home and surf the web,WTF!?! Does anyone know whats goin on lol I tried uninstalling IE altogether and reinstalling IE after rebooting but it still says the same thing!
errrr..........help?:confused4

[Host Factory]

try clear the computer cashe, go in to command promt (in vista, you have to run it as admin) and type
ipconfig /flushdns

[Decker]

Check under tools - internet options - connections - lan settings, untick anything to do with proxy settings.