If you don’t know Internet Explorer 10 in Windows 8 comes in two versions desktop and Metro, where Metro version is set as the default. It doesn’t matter if you set any other desktop browser such as Firefox or Chrome as the default one where by default links always open in Metro IE. Here is how to set any other desktop browser as the default in Windows 8 Developer preview.
Setting Firefox as default browser
Open desktop Control Panel>Programs> Default Programs>Set your Default Programs
Select Firefox or any other browser you want to set as default one, click Set this program as default.
Click Ok to save changes and from now onwards Firefox or other browser you set above is the default one.
Now clicking on “IE” icon on metro start screen opens desktop Internet Explorer instead of Metro one, don’t ask me how to get back metro version.