Rightclick on the blank desktop and choose Screen Resolution, lower the resolution to make objects larger and more readable but still maintains picture sharpness and correct proportionality.
If it's still too small or you want a higher setting for better picture sharpness, then select Make Items Larger or Smaller and change DPI to 125%, Apply, restart. You can change it to any size you want. DPI Display Size Settings - Change
Let us know if this helps or you need more options.