Follow these instructions to determine whether your computer is running a 32-bit or a 64-bit edition of Microsoft Windows.
Identify 32-bit and 64-bit editions of Windows 7 and Vista
If your computer uses Windows 7 or Vista, then do the following:
Choose Start > Control Panel.
Do one of the following:
If the Control Panel is in a category view, then click System And Maintenance. On the next screen, click System.
If the Control Panel is in Classic View, then double-click System.
Look for 32-bit Operating System or 64-bit Operating System next to System Type.
Identify 32-bit and 64-bit editions of Windows XP
If your computer uses Windows XP, then do the following:
Choose Start > Control Panel (or Start > Settings > Control Panel).
Do one of the following:
If the Control Panel is in a Category View, then click Performance And Maintenance. On the next screen, click See Basic Information About Your Computer.
If the Control Panel is in Classic View, then double-click System.
In the System Properties window, click the General tab.
If the text beneath System says Microsoft Windows XP Professional x64 Edition, then you are running a 64-bit edition of Windows XP. Otherwise, you are running a 32-bit edition.
Additional information
The System item in the Control Panel shows basic information about your computer, including the specific edition of Windows that is installed.
