Guidelines to change screen resolution from 640x480 pixels to 800x600 pixels
Click the "Start" button in the bottom left corner of the screen and select "Settings" and then "Control Pannel"
In the next window you select (double click) the "Display" icon
The next window has several tabs. Select the tab that reads "Settings". You get the following screen (or something similar).
Use the slider in "Screen area" and bring it up one notch, from 640x480 to 800 by 600 pixels. Click OK and see if it works for your computer. You may have to increase the "Colors" as well. "True color" or 16 million colors is the one preferred but take the highest setting in the 800 by 600 pixel resolution.