How to find out if your PC or Laptop is running Windows 32 bit or 64 bit operating system

Windows XP

   1.  Click on the 'Start' button at the bottom left corner.
   2.  Right-click on 'My Computer'.
   3. Click on 'Properties'
   4.  Look at the text shown under 'System'. 
           If it says 'Microsoft Windows XP Professional Version xxxx', it is 32-bit.
           If it says 'Microsoft Windows XP Professional x64 Version', it is 64-bit.

Windows 7

   1.  Click on the Windows Logo on the bottom left corner.
   2. Right-click on 'Computer'.
   3. Click on 'Properties'
   4. Look at the System Type line in the middle of the screen.

Windows 8

   1.  Open the Windows Control Panel
   2.  Choose 'System and Security'
        (if you are looking at large or small icons, this option will not be there.  In that case, ignoring this step and move
         on to the next one)
   3.  Choose 'system'
   4. Find the System area, located under the large Windows 8 logo.