Changing Default Browser

Select the "Internet Options" item from the tools menu.

Click on the "Programs" tab.

Check the box stating "Internet explorer should check to see whether it is the default browser"

Apply the setting.

Restart internet explorer.

From the "File" menu, choose preferences.

Select "Default Browser".

Check the appropriate boxes.

Choose "File" menu and select "Preferences".

Expand "Advanced" tab and select "System". 

Choose the appropriate file types.