This step-by-step article describes how to determine whether a computer is running a 32-bit Microsoft Windows operating system or a 64-bit Microsoft Windows operating system. To determine whether your computer is running a 32-bit Windows operating system or a 64-bit Windows operating system, examine the system information. To do this, use one of the following methods.

Note Intel Itanium-based computers can only run 64-bit versions of Windows. Intel Itanium-based computers cannot run a 32-bit Windows operating system. Currently, 64-bit versions of Windows only run on Itanium-based computers and AMD64-based computers.

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Windows Vista

Method 1

1.	Click Start, type system in the Start Search box, and then click system in the Programs list.
2.	The operating system appears as follows: • For a 64-bit version operating system: 64-bit Operating System appears for the System type under System. • For a 32-bit version operating system: 32-bit Operating System appears for the System type under System.

Method 2

1.	Click Start, type system in the Start Search box, and then click System Information in the Programs list.
2.	The operating system appears as follows: • For a 64-bit version operating system: x64-based PC appears for the System type under Item. • For a 32-bit version operating system: x86-based PC appears for the System type under Item.

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Microsoft Windows XP Professional

Method 1

1.	Click Start, click Run, type sysdm.cpl, and then click OK.
2.	Click the General tab. The operating system appears as follows: • For a 64-bit version operating system: Microsoft Windows XP Professional x64 Edition Version < Year> appears under System. • For a 32-bit version operating system: Microsoft Windows XP Professional Version< Year> appears under System. Note <Year> is a placeholder for a year.

Method 2

1.	Click Start, click Run, type winmsd.exe, and then click OK.
2.	In the details pane, locate Processor under Item. Note the value. • If the value that corresponds to Processor starts with x86, the computer is running a 32-bit version of the Windows operating system. • If the value that corresponds to Processor starts with ia64 or AMD64, the computer is running a 64-bit version of the Windows operating system.

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Microsoft Windows Server 2003

Method 1

1.	Click Start, click Run, type sysdm.cpl, and then click OK.
2.	Click the General tab. The operating system appears as follows: • For a 64-bit version operating system: Microsoft Windows Server 2003 Enterprise x64 Edition appears under System. • For a 32-bit version operating system: Microsoft Windows Server 2003 Enterprise Edition appears under System.

Method 2

1.	Click Start, click Run, type winmsd.exe, and then click OK.
2.	In the details pane, locate Processor under Item. Note the value. • If the value that corresponds to Processor starts with x86, the computer is running a 32-bit version of the Windows operating system. • If the value that corresponds to Processor starts with EM64T or ia64, the computer is running a 64-bit version of the Windows operating system.

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