To do this:-right click on a blank area of the desktop and select Personalize and then click Display Settings.There you can change the Screen resolution , colors as well as the monitor refresh rate by clicking the Advanced tab.A refresh rate of at least 75 Hertz generally produces less flicker.
Monitor size Recommended resolution
15-inch monitor 1024 x 768
17- to 19-inch monitor 1280 x 1024
20-inch and larger monito 1600 x 1200