I suggest installing another browser (temporarily), such as Firefox or Opera, with default settings.
If the same problem occurs then it's more likely than not external to whatever browser you use - could be firewall or other security settings in OS or 3rd party programs.
If the problem doesn't occur, then it must be a setting within IE 7. You could then try removing and reinstalling with default settings.
Also if you have some IE plugins to eliminate ads you could try removing them, to try to return to "default" IE7 installation.
SD