Windows Vista or Windows 7
If you have Windows Vista or Windows 7, there are two methods to determine whether you are running a 32-bit or a 64-bit version. If one does not work, try the other.
Method 1: View System window in Control Panel
1. Click Start

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

, type system in the Start Search box, and then click System Information in the Programs list.
2. 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.
Windows XP
If you have Windows XP, there are two methods to determine whether you are running a 32-bit or a 64-bit version. If one does not work, try the other.
Method 1: View System Properties in Control Panel
1. Click
Start, and then click
Run.
2. Type
sysdm.cpl, and then click OK.
3. 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 System Information window
1. Click
Start, and then click
Run.
2. Type
winmsd.exe, and then click OK.
3. 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
ia64 or
AMD64, the computer is running a
64-bit version of Windows.