Is it 32bit or 64bit Windows OS?

I always had this question of how to determine if the Windows OS that you are running is a 32 bit or a 64 bit, everytime I used to google for the same and find the link, but then thought what the heck, let me blog it so that it would be useful for others, if there are any :)

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 typeSystem. under • For a 32-bit version operating system: 32-bit Operating System appears for the System typeSystem. under

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.

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>System. appears under 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.

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 System. appears under • For a 32-bit version operating system: Microsoft Windows Server 2003 Enterprise EditionSystem. appears under

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.

Above text is taken from this link : http://support.microsoft.com/kb/827218