Hey, you can use "Prnt+Scn" button to help you capture screenshot from desktop, then paste it on MS paint, and you can save the picture. If it doesn't work, you can use some screen recording program, which can help you record screenshot
with high quality.
The one I used can capture anything on computer screen to image file, and you can select any portion of the screen to take screenshot. And it also can help you save the file to standard image format, such as JPG, GIF, BMP, PNG etc.