It sure can be hard keeping up with things in computer-land.

There's a not-so-obvious thing called the "architecture" of your computer's processor which has mostly changed now for new machines, but many people are not finding out what it means to them until it costs them some money. Basically the way that the processor counts is based on binary numbers, and everybody kinda understands that machines count in ones and zeros. What they don't understand is how computers have grown up, from 16-bit systems like DOS and Windows95, to 32-bit systems like Windows98, WindowsME, and Windows XP. To make it even more confusing, XP, Vista and Windows 7 all come in either 32- or 64-bit versions, so you can't just know which one applies without digging a little.

One last thing: it's imporant for you to know that you CAN load a 32-bit version of Windows onto a computer with a 64-bit processor. This leads to all kinds of crazy problems, like 32-bit Windows only acknowledging 3.2 Gigabytes of the 4gigabytes of memory you bought (32 bit Windows systems can't count any higher than 3.2.GB when enumerating RAM), but generally speaking you won't ever buy a new 64-bit computer that does not have a 64-bit OS on it.

Windows Vista or Windows 7

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.

Windows XP

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.