First right click on the desktop and then left click on Properties
from the menu that appears.
The Display properties
dialogue box will appear, click on the Desktop
tab as shown below.
Next, click on the small arrow next to the current background colour (as seen above) to view available colours.
A small selection of colours will appear, these are basic colours, if you want a more varied selection then click on other
and you will be presented with a wider choice.
When you have chosen a colour you can preview it by clicking on the apply
button, when you are happy with your choice simply click the OK
the background colour will only change if don't have a background image on your desktop.