Windows has only two options for getting screenshot - copy to clipboard entire screen by PrintScreen key or copy to clipboard snapshot of active window by Alt+PrintScreen. Screen Beagle allows you to copy to clipboard or save to file entire screen as well as selected area of the screen. Just activate Screenshot feature of Screen Beagle and select area by mouse. Note that selected area is editable, so you can change size and position by dragging border and selection. Information window that can be shown over the screen image shows everything you need: selection start and end points, selection size and even 2x zoomed screen image under mouse cursor for most accurate selection.
Activation: tray icon menu, screenshot tray icon (customizable) or screenshot hot key (customizable).
When Screenshot feature is activated, you can copy and save entire screen or selected area from context menu or with hot keys:
Copy screen Ctrl+C
Save screen Ctrl+S
Copy Selection Alt+C
Save Selection Alt+S
More details: http://greatis.com/utilities/screenbeagle/screenshot.html