In you're only opening one browser, then 'go'ing twice. What you have is like opening a browser window, typing in the Address bar, then typing in that same address bar again.
You need to open two browsers.
EG:
var firstBrowser = new IE();
var secondBrowser = new IE();
firstBrowser.GoTo("www.google.com");
secondBrowser.GoTo("www.cnn.com");
The above is written from memory and therefore may not be 100% exactly correct, but is the general idea to get two browsers open that you can work with.