Windows 8

Step 1: On your keyboard press Win+Q to lunch search option and then inside search field type control panel.
 

Step 2: From left pane launch Control Panel.
 

Step 3: When Control Panel window opens up launch Default Programs.
 

 

Step 4: Now click Associate a File Type or Protocol with a Program link.

 

 

Step 5: Inside the new window that opens up, scroll the list all the way down until you find MAILTO under Name field and double-click on it.

 

 

Step 6: A new small window will open asking you how do you want to open this type of link. You will have few programs to choose from e.g. Outlook, Google Chrome, Windows Live Mail etc. Choose your preferred program and you’re done.