I cant figuer out how to change my back ground

For the Acer Aspire One with Windows XP...
1. click on start at bottom left of desktop
2. on the start window, click on Control Panel
3. on the Control Panel window, double-click on Display
4. on the Display Properties window, click on Desktop tab
5. on the Desktop, click on Browse button
6. browse to picture you want for your desktop background and double-click on it
7. on the Desktop Position, click on V and select Center, Tile or Stretch
8. click on Apply to get new background immediately or OK to exit then change background

If you windows vista or seven basic installed there is no option to allow you to change the background