You may have to hold it in for a few seconds.

Try right-clicking a blank part of the desktop, select Graphics Properties and see if you have any advanced options, such as arrows to reposition the desktop.

Alternately, in Control Panel there may be a setting for your graphics driver.

How do I center a window on my screen?

This is not exactly for centering, but lets you move the window left and right (and up and down) easily.

Focus a window.
Press Alt + Space .
Press M (for “Move”).
Use the arrow keys to move the window exactly where you want it.
Press Enter when done.

But not for the desktop itself. It's using keyboard shortcuts to replace mouse clicks within the little 'Restore, Move..etc' icon at the top left of the window title bar.

Play with those a little bit--you might find an adjustment that moves it to the left as needed.

On my Samsung, they're along the bottom. The first button brings up the built-in adjustment program, second one moves me among the adjustment options, third one changes the setting. You can't do much wrong that you can't fix. Hope this helps!

I never imagined such a quick response so I didn't even bother checking back til this AM.

LeftofCenter nailed it. I should have mentioned this was a laptop. I always called screens, whatever they are attached to, monitors for some reason.

Alt space plus M did it after a couple of tries.

Weird thing is: this right shift of viewing plane happened as I dragged my hand across the keyboard unintentionally. I couldn't duplicate that move again for a million dollars.

Again, thank you my DU brother and sisterhood! Democracy rocks!