Windows

• 1). Click the Windows logo or "Start" button in the bottom-left corner of the screen.
  
  
• 2). Click the "Run" link, or click the "Search programs and files" field.
  
  
• 3). Type "winver" without quotation marks, and press "Enter." The computer displays a popup window, showing the installed version of Windows.
  
  
• 4). Click "OK" to close the window.
  
  

Mac OS

• 1). Click the Apple logo in the upper-left corner of the desktop.
  
  
• 2). Click "About This Mac." The computer displays a popup window showing the installed version of Mac OS.
  
  
• 3). Click the red jewel in the upper-left corner of the window to close the "About This Mac" window.