Windows 7

• 1). Right-click anywhere on the desktop and select "Personalization" from the contextual menu.
  
  
• 2). Right-click on a theme on the first row. Select "Delete Theme" from the contextual menu.
  
  
• 3). Click the "OK" button when the confirmation box appears.
  
  

Windows XP

• 1). Click the "Start" button and select "Control Panel." Double-click the icon for "Display."
  
  
• 2). Go to the "Themes" tab. Select a theme from the drop-down box.
  
  
• 3). Click the "Delete" button.