IE7 and no access to random websites

[Guest]

I have vista x64 and using the 32 bit or 64 bit versions of IE7 I cannot
access certain websites (one site I wanted to access for my email is
www.orange.net, www.orange.co.uk works fine untill I try to log in for my
email!), says no connection available, you are not connected to the internet
or the site is down, blah blah blah!

A quick install of firefox and I can access these sites, is this vista or IE7?

 

[Guest]

I have the same problem. Only Google works for me so far. Dell, yahoo,
microsoft,msn,firefox, foxnews, don't work. Windows update doesn't work
either.