Can you help me fix my internet connectivity problem with IE8?

I need to do an online exam that ONLY works with Windows (so I can’t use my Mac), and it ONLY works with Internet Explorer.

Here is the problem:

One day, something popped up on my g/f’s PC. She just clicked without knowing what the hell is going on.

So now, the internet connection is strong, and if she uses Safari it works great. But something is blocking Internet Explorer from getting online. When I open IE it goes to the error page “Diagnose Connectivity Error.” But when I diagnose it, it says connection strong.

What could be blocking the IE8?

I disabled McAfee . . . what’s left?