Windows 7 lets you alter the picture you see on your desktop. This is called the Desktop background, or Desktop wallpaper.
To chage your Desktop Wallpaper, click anywhere on the desktop together with your right mouse button, and you ought to see a menu appear:

One of the items on the menu allows you to personalize your desktop screen. So click on Personalize with your left mouse button to see a window appear. This one:

In case you need to set background wallpaper, however, select Desktop Background from the bottom left. The default is called Harmony.
The main area in the screen above let’s you pick a Theme from the obtainable list. A Theme sets not only your desktop background, but as well as a screensaver, the colour of windows, sounds, and mouse pointers. And all that with click!
When you click on Desktop Background you ought to see something like the following:

You can select a picture from the ones available by clicking on it together with your left mouse button. Your desktop background will then modify. To make the modify permanent, click the Save Changes button at the bottom.
In the event you have a picture of your own, you can use this in lieu of the ones built-in to Windows 7. To set your own picture, click the dropdown list at the top, where it says Windows Desktop Background:

Here, we have moved to the Pictures Library folder to see what images are available. Another option is to click the Browse button. When you do, you’ll see a dialogue box appear:

Browse to the folder where your images are & click OK. They have a folder called York with some images in it, so we have chosen that.
When you click OK, you’ll see the images in that folder

Select the picture you need to appear on your desktop from those available. In case you would like a slideshow of all the images in the folder, then click the Select All button. In case you click the Select All button then the dropdown list at the bottom becomes available:

Another area to play around with is the Picture Position. Click the black arrow to see a dropdown list:
This list lets you select how often each picture in the slideshow is displayed before moving on to the next. The default is ten seconds.

Select each in turn and watch what happens.
When you are happy together with your choices, click Save Changes. You will then be taken back to the first screen:
Windows Colour
Another fascinating area to play around is the Windows Colour area, circled in red in the picture above. Click the link to see the following screen:

Things like the beginning menu, the taskbar, & the areas around programmes can all have the same colour process. The default is called Sky. Click of the other colours above & watch what happens to your Taskbar at the bottom. Click the round Start button on the left of the Taskbar & you’ll see that its colour has changed. Uncheck the box that says “Enable transparency” & you’ll see a deeper colour for the you have selected.
In case you don’t like the colours obtainable, click the arrow to the left of Show Color Mixer. Then play around with the controls. To get back to the default colours, click the colour square in the top left of the screen, which is Sky.
In the next section, we’ll have a closer look at the Taskbar in Windows 7.