On most PCs and laptops, there's a button that says PrtScr. Using that, you can print your screen, effectively copying what is currently on-screen, just like Ctrl + C does. As such, you can paste it in an image editor, such as MS Paint, and upload it to Imgur, for example, to share the pics here. Alternatively, download Lightshot, which simplifies the whole process by allowing you to upload a screenshot immediately.