Using System Properties

• 1). Go to "Start," then click "Run." Type "Sysdm.cpl" into the text field, and click "OK" to launch System Properties.
  
  
• 2). Note the entry found under the "System" field, located in the "General" tab. A 64-bit version of Windows is listed as "Microsoft Windows XP Professional X64." Otherwise, the 32-bit version is listed as "Microsoft Windows XP" followed by its "Home" or "Professional" counterpart.
  
  
• 3). Click "OK" to exit the System Properties screen.
  
  

Using System Information Screen

• 1). Go to "Start" followed by "Run." Type "Winmsd.exe" into the text field, and press "OK."
  
  
• 2). Locate the "Processor" entry from the main "System Summary" details pane.
  
  
• 3). Note the processor description under the "Value" column. If such information starts with "Ia64" or "AMD64," this indicates the presence of a 64-bit Windows XP edition. Otherwise, the processor's description will state "X86."
  
  
• 4). Go to "File" and click "Exit" to close the System Information screen.