32 or 64 bit

How do I find out if I have a 64-bit operating system?

Often 32-bit operating systems are not explicitly named or called out as 32-bit systems in any place that is obvious. However, you can check the operating system on your computer while it is running:

To check your version of Windows:

1. Click the Start menu.

Right-click Computer (or in some cases, it says "My Computer").

Select Properties. A System Properties dialog box displays your computer information, including the operating system.

If you are running 64-bit Windows, the dialog box says it. Look at the System information on Windows XP as "x64 Edition,"

or the System type in Windows 7 or Windows Vista:

Otherwise, assume that you have a 32-bit system