Saving an image

When I first had my Vostro last November I was able to use a combination of keys..Shift+windows key + s key and the a window would open and allow me to use the mouse and select an area of the screen I wished to copy.

When I clicked the mouse a new window at the bottom of the screen would pop open and the image that I had copied would appear there. When I clicked on this window another larger window appeared in the middle of the screen and then I could save the image.

The above no longer seems to work.

Not sure what I have done to eliminate shortcut of saving an image.

I have looked at https://www.dell.com/support/kbdoc/en-au/000131432/keyboard-usage-and-troubleshooting-guide but have not been able to find a solution to my problem.

Thank you for any suggestions,

Reainderman3