Try this:
1. Open Internet Explorer.
2. Go to Tools > Internet Options... Within the Internet Options window, click on the Programs tab. Check the box titled: Internet Explorer should check to see whether it is the default browser.
3. Click on Apply and then OK.
4. Close Internet Explorer and then start the program again. An Internet Explorer message should appear saying Internet Explorer is not currently your default browser. Would you like to make it your default browser? Uncheck the Always perform this check when starting Internet Explorer box, and click on Yes. Internet Explorer is now your default browser.
If it is not your default browser and the message does not appear, restart your computer and launch Internet Explorer again.