Clicking on hyperlinks does not open a webpage

Hello! From last two weeks, I have noticed this one thing while using my computer and when I am connected to Internet. When I click on a certain link while using a program or on the Internet, it takes me to the Windows Explorer on PC rather the intended location. Like I was using Optimizer Pro and I clicked on the link ‘Register Now’ it did not take me to a web page but it took me to the file folder where the Optimizer Pro is. I am windows 7 user, can anyone help? Thanks in advance.
