So it's working in so much as the buttons are being read by the PC, but just not working in games? I'm not sure how that's possible for the controller to not work at all if you've told the game in the options menu to use a gamepad/joystick instead of the keyboard/mouse. In fact, I've never heard of that happening.
Are you sure
the gamepad is working correctly (the buttons are actually being recognized by the OS - have you tested that with a mapping program/the driver utility that shows you what buttons you pressed to confirm that)? And are it's drivers even supported for Windows 7? Does the game itself actually support the use of a gamepad? Did you set the buttons up in the game's joystick options? And which game(s) are we talking about here?
Worst case scenario, I'd recommend that you give JoyToKey a try to map the controller independently of the drivers and the games themselves, to check it actually works if nothing else. That will always work if you leave it running in minimized mode in the system tray while gaming (this is what I do because the game's mapping doesn't always work properly). You can get it here
(it's 100% free and safe).
Just note, the left and right joysticks are a slight pain to configure in there. I can help you with that if you want to try it out.