How to determine whether your operating system is running on 32 Bit or 64 Bit

If you have Windows Server 2003 

There are two methods to determine whether you are running a 32-bit version or a 64-bit version. 

Method 1: View System Properties in Control Panel

Click Start, and then click Run.

Type sysdm.cpl, and then click OK.

Click the General tab. The operating system is displayed as follows:

For a 64-bit version operating system,  Windows Server 2003 Enterprise x64 Edition appears under System.

For a 32-bit version operating system,  Windows Server 2003 Enterprise Edition appears under System.

Method 2: View the System Information window

Click Start, and then click Run.

Type winmsd.exe, and then click OK.

When System Summary is selected in the navigation pane, locate Processor under Item in the details pane. Note the value.

If the value that corresponds to Processor starts with x86, the computer is running a 32-bit version of Windows.

If the value that corresponds to Processor starts with EM64T or IA-64, the computer is running a 64-bit version of Windows.

If you have Windows Vista or Windows 7

There are two methods to determine whether you are running a 32-bit version or a 64-bit version. 

Method 1: View the System window in Control Panel

Click Start, type system in the Start Search box, and then click system in the Programs list.

The operating system is displayed 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: View the System Information window

Click Start, type system in the Start Search box, and then click System Information in the Programs list.

When System Summary is selected in the navigation pane, the operating system is displayed 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.

If you have Windows XP

There are two methods to determine whether you are running a 32-bit version or a 64-bit version. If one method does not work, try the other method.

Method 1: View System Properties in Control Panel

Click Start, and then click Run.

Type sysdm.cpl, and then click OK.

Click the General tab. The operating system is displayed as follows:

For a 64-bit version operating system,  Windows XP Professional x64 Edition Version < Year> appears under System.

For a 32-bit version operating system,  Windows XP Professional Version <Year> appears under System.

Note <Year> is a placeholder for a year.

Method 2: View the System Information window

Click Start, and then click Run.

Type winmsd.exe, and then click OK.

When System Summary is selected in the navigation pane, locate Processor under Item in the details pane. Note the value.

If the value that corresponds to Processor starts with x86, the computer is running a 32-bit version of Windows.

If the value that corresponds to Processor starts with IA-64 or AMD64, the computer is running a 64-bit version of Windows.