change size of taskbar and desktop icons

The icons on my desktop icons suddenly got huge and all could not fit on the screen. Simultaneously, the taskbar icons got very small. I had not done anything intentionally to cause this. I tried clicking settings I got pressing the windows button (lower lft of screen). I followed the directions to resize the icons. Nothing worked to resize the taskbar. I did succeed resizing of the desktop except all he options (small, medium, large extra large) were either much larger or much smaller then they had been. I have never changed either of these settings since I upgraded to Wndows 10. Any help please?

Thanks for the quick - and helpful response at least regarding desk top icons. However, this procedure did not work for taskbar icons. Any help ith that?

Thanks very much for prompt, very understandable and successful instructions. An A+ to you.