Screen resolution is the number of dots (pixels) that make up the computer graphics picture, in the format of horizontal size by vertical size. For example: a screen resolution of 640x480 means that there are 640 dots that make up the horizontal size of the display and 480 dots for the vertical size of the display. The number of dots that the screen is made up from, the more information that can be displayed on the screen and the sharper the image.
The screen resolution can be changed from the display properties:-
We recommend a minimum resolution of 1024x768, but if your computer is capable of anything higher then use it. A word of warning, a high resolution on a small monitor may result in the text becoming too small to read. You may have to compromise for optimum performance.