A common question that we get here at Tech Support is: how can I tell if my computer is 32 or 64-bit? To find out what type of system that you have is easy. Go to My Computer on your Desktop. Right-click on the icon and select Properties. Under the System component list, look for the System type. The menu should state whether your computer is 32-bit or 64-bit Operating System. An alternate way to get to this menu is to go to Control Panel -> System. The information that is listed is the same.
Once you know what type of system that you have, it is critically important when selecting the type of software to install. Many manufacturers offer both 32-bit and 64-bit versions of their programs, so before you buy, you need to have this information handy. You cannot run a 64-bit program on a 32-bit computer, because the system lacks the processor speed and memory. But, you may be able to run a 32-bit program on a 64-bit machine depending on the manufacturer's specifications. For more on 32-bit and 64-bit Windows, go to Microsoft Support: http://www.microsoft.com/windows/windows-7/compare/32-bit-64-bit-faq.aspx