Over the years I've used a lot of tools to get screenshots. My old standby is Paint Shop Pro (copyright 1991-1997 it says on the splash screen, and I recall I deliberately didn't stick with an upgrade that introduced complicated stuff I didn't want, like layers.) I like it because I can set up a time delay for a shot which lets me get tooltips and the like ready when the capture happens.
Alas, on this Windows 8 machine with a second screen, something confuses Paint Shop and it doesn't capture the whole screen. I experimented a bit with the Snipping Tool that comes with Windows, but it doesn't have a time delay or a keystroke, so I can't get tooltips, context menus, or anything else that requires me to interact with the app before the shot.
I got desparate and started using the PrtScrn button on my keyboard. Your keyboard probably has one. I often type Shirt-PrtScrn but I just checked and the Shift is unnecessary. This captures the whole screen (or both if you have two) and puts it in the clipboard buffer. From there I can paste into whatever I edit images with (usually Paint Shop to be honest) and then crop to the part I want.
So far this is boring. I mean really, this is what you could have done TWENTY YEARS ago. And it's been fine for me except that cropping part. But yesterday I learned about Alt PrtScrn. It gets you just the current window! And if you let go of Alt before Prt Scrn, the alt is not passed along to the underlying app either. This is going to save me some seriously annoying cropping.