Windows 32 or 64bit?

How can I tell if I am running a 32-bit or 64-bit version of Microsoft Windows?

If you are not sure whether you your computer is running a Windows 32-bit or 64-bit version, do the following:

Windows XP

1. Click the Windows Start menu, right-click My Computer and select Properties.
   Note: the My Computer icon may be located on your desktop instead of in the Windows Start menu.
2. If you don't see 64-bit explicitly stated in the General Information section, you have a 32-bit version of Windows.

Windows Vista

1. Click the Windows Start menu and navigate to Control Panel > System and Maintenance > System.
2. Under System, the system type indicates whether you have a 32-bit or 64-bit version of Windows.

Windows 7

1. Click the Windows Start menu, right-click on Computer and select Properties. 
   Alternate method: Click the Windows Start menu, navigate to Control Panel > System and Security > System.
2. Under System, the system type indicates whether you have a 32-bit or 64-bit version of Windows.