It's called "Print screen" usually.

Top right.

Mighty-On a laptop, where i the "prtsc" button at?

No it won't harm it, but downloading it isn't how you capture an image of the front page.

There is a key on your keyboard that allows you to take screenshots of anything on your screen. If your on a desktop, there is a key that says "prtscn." Press that and paste it into whatever program your using. On a laptop/netbook, you have a key that says "prtsc," BUT you also have to hold down the Fn key. The Fn key is located down at the bottom left hand side. Then paste it as before.

Hope this helped.