With most computers you can just press Control and Print Screen and it will snap your whole desktop – but then you will need to open it and crop it to make it useful. I like to use a program call Screenshot Captor. It can be downloaded from this link: https://www.donationcoder.com/Software/Mouser/screenshotcaptor/downloads/ScreenshotCaptorSetup.exe
After installing and running the program there will be an icon in the tray.
If you right click on it you can get a menu that looks like this.
If you chose Grab Selected Area, you will have the ability to select what you want an image of and then save it as a file or copy it to the clip board. This is also very useful when you want to share what you see on your computer screen