Help! I can no longer access "any" .gc.ca sites

Hi, I'm new to the forum and come equiped with a problem.
All of a sudden, I can no longer access "any" .gc.ca sites.
These are Government of Canada sites and I believe that either Internet Explorer or Windows fire wall has corrupted the ability of my system to show them.

Message I get = Windows Internet Explorer Cannot open the page.
I can go anywhere in the world except for those sites.
Can anyone help with this problem?
I have contacted Microsoft,Norton Anti virus etc. and don't get to firs base with them.