Playing pc games with a ps2 controller

I've been reading about how it works and I've done what is says. i just cant seem to get it to respond at all. i have windows 7 installed and my computer recognizes the PS3 controller. am i actually able to use it or is it impossible at this point in time?

The title says PS2. 
The post says PS3. 
Help me out here.

" The title says PS2. The post says PS3. Help me out here. "

here ya go
 http://www.motioninjoy.com/download
 
I guess you'll probably gona be using USB instead of bluetooth
here's the guide, nothing too complicated but you will have to follow it
 http://www.motioninjoy.com/help/sixaxis-dualshock-3-connecting-usb

Although it's easier to do on win32/mac OS, it's also possible on win64-bit by launching the computer in ''test'' mode. Follow the link posted above though. ^^^

Using Motioninjoy, which thankfully was supplied by doe3879, is your best bet. It covers 4 different kinds of controllers on the market and also emulates a 360 Gamepad. All with a PS3 controller.

Back when I had one all I had to do was plug it in and it worked. I think I had Vista at the time though so it may work differently with Windows 7.