Greenshot - How to Capture Screenshots
Browse to download the newest version of Greenshot by clicking on link below. There you will see a download button to download Greenshot.
Greenshot link:
After you have downloaded and installed Greenshot, a shortcut icon 
will appear on your computer’s taskbar, near your system’s clock area.
By default, Greenshot is designed to run automatically with Windows start up, so there will be no need to start it manually because it is already running in the background, just waiting for you to interact with it.
To Create a Screenshot
1) You can create a screenshot, either by using the Print Screen key on your keyboard.
2) Right clicking the Greenshot icon and choosing your desired option capturing.
Please note: If you are using a laptop you may have to press the Fn key along with the Print Screen key to capture your shot.
From your Print Screen key, the capture mode should be set to the region capture which allows you to select the part of your screen to be captured. You will see a crosshair pointing out the mouse position on the screen. Click and hold where you want one of the corners of your screenshot to be.
Still holding down the mouse button, drag the mouse to define the rectangle to be shot. When the green rectangle covers the area you want to be captured in your screenshot, release the mouse button.
Note: Click Esc if you’d like to exit screenshot mode before capturing a shot, whether to recapture or just to terminate the current capture.
Next, unless you have changed the default settings, Greenshot will then ask you what you want to do with the screen shot you’ve just taken in a box as below.
You can choose the application to open the screenshot. If unsure or you’d like to edit the screenshot, select Open in image editor. Here you will be able to draw on the screen shot you took, modify the image in other ways, save the image if needed, copy it to the clipboard and paste it to email, Microsoft Word, Excel or other applications.
To modify your Greenshot preferences, navigate to Preferences from you icon shortcut and make your desired changes in the dialog box as you see below.
One you start using Greenshot, you may find it useful for all sorts of tasks.