Problem with Internet Explorer and Mozilla Firefox

Hello,
I am using Windows 7 OS and I was using Internet Explorer as my browser. But IE is not very efficient so I opted for Firefox. I downloaded Firefox 17 and installed it. Problem is I can't make it my default browser. I have tried setting it several times but it doesn't work. Every time I open a link it opens through IE not Firefox. I tried the option to deselect the option from IE that makes it the default but no luck yet. What should I do?
