Help: 32-bit or 64-bit?

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

Windows 8

Right-click the "Start" button.
Choose "System" 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 Vista or Windows 7

Open the "Start" menu.
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

Open the "Start" menu.
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; otherwise, it is 32-bit.