How do I know whether my version of Windows is 32-bit or 64-bit?

Windows Vista or Windows 7

• Click Start.
• Right-click Computer.
• Choose Properties from the context menu.
• In the "System" section, look for "System Type." It will say either "32-bit Operating System" or "64-bit Operating System."

Windows XP

• Click Start.
• Right-click My Computer.
• Choose Properties from the context menu.
• Look just below the "Microsoft Windows XP" label for the particular edition of XP (for example, "Professional x64 Edition" or "Home"). If the edition contains the word "x64" then your machine has a 64-bit version of Windows XP.