The best and easiest way to insure you meet the minimums is to look through the DXDIAG utility.
You can start this utility by going to "Start", then "Run", and then typing in "DXDIAG" and press <ENTER>.
The panel is shown below.
Operating System: Windows 98, ME, 2000, or XP
Computer Memory: 256MB or higher
DirectX 9.0 or later
Video Card: A 32MB video card with support for hardware 3D acceleration, or better
Internet Connection: A 33.6K modem or faster Internet connection
Sound Card: DirectX compatible sound card
Input Devices: Joystick and mouse.
Optional: Speakers and microphone are optional.
When DXDIAG starts up, there is a progress indicator in the lower left corner of the screen, just above the "Help" button. You must wait for it to disappear before perusing the data.
After the progress indicator has disappeared, you will be able to look at the center of the screen and find your "Processor" description. Directly underneath is the amount of memory your computer has, and the last line indicates the DirectX version installed on your computer.
If you find you need to update your version of DirectX, you can do so at Microsoft's DirectX Center.
If all this looks good and meets or exceeds the minimum required for the game, then let's take a look at some information. Right this way!