Normally, a computer’s screen resolution is at its maximum by default, but in some cases, you need to change it manually to get the most out of your computing experience. If you don’t have an exceptionally slow machine, it’s definitely worth the effort.
Here’s how to change your screen resolution:
Go to your Windows XP’s desktop and right click on an empty space. Select “Properties”.

In the “Display Properties” window that appears, navigate to the “Settings” tab on the right.
Move the slider in the bottom-left corner of the window to change your computer’s screen resolution: left for lower resolution, right for higher resolution. Try moving it to the far right for maximum resolution. Press “Apply” and see if everything works.
displayproperties-resolution
A dialog box will pop up after your screen adjusts itself. If everything’s OK, press “Yes”.
If your screen looks stretched or has a lot of lag, press “No” or wait 15 seconds to revert to the old settings. Find a resolution that you like.