Have you ever lost a window while working in Windows? You might see the program on the taskbar, but you can’t seem to get to it. In some rare cases, the window may have been shifted off-screen and you won’t be able to click on it and because you can’t, you won’t be able to drag it back to the visible desktop.
Solution 1:
Hold the Win key and press the left or right arrow until it jumps back into the visible desktop.
Solution 2:
Sometimes, the Win key method does not always work. What you can try is to snap the window to your mouse cursor. If you are on Windows right now, try pressing Alt-Space. You may notice this menu pops up in the corner:

If you choose “Move” (M is the keyboard shortcut), you’ll notice you can move the Window with your arrow keys. This is meant for a precise way to position windows with the keyboard. (You can also hold Ctrl to be even more precise to the pixel.)
The trick is that after moving the window with the keyboard, if you now move the mouse, the Window will snap to the mouse cursor. Now the window will now pop back into the visible area and you can just click to drop it back.
Yay!
Shortcut sequence: Alt-Space -> M -> arrow key (any) -> move the mouse