(1) First of all take your mouse pointer to top right corner and wait for the charms bar to arrive.

(2) Once the charm bar appears, select Settings charm.

(3) Then select Change PC Settings Option.

(4) This will take you to the new Control Panel. Here in the Personalize tab, click on Start Screen option.

(5) At the bottom, you can see a bar representing several colors. You can select any color of your choice from the bar and that color will instantly become your Start screen's color.