To use a wired controller as a gamepad all you need to do is plug it in and follow these instructions,
http://support.xbox.com/support/en/us/nxe/kb.aspx?ID=906347&lcid=1033&category=hardware
However to use a wireless controller a wireless dongle must be purchased separately.
The original Xbox controller doesn't work on the 360.
The Xbox 360 controller will not work on the Xbox one. You will have to use an Xbox One controller.
No.
Yes, if you use a gamepad. The game supports the XBox 360 controller and I believe it accepts other controllers too.
Yes you can.
no
There is no way to use your existing Xbox 360 controller on your PC. However, Microsoft have released a PC controller which is a Xbox controller.
simply, yes... you can play COD 4 with any gamepad...
The black elite controller will work on any model of xbox 360
No
Yes.
Yes, if you install the files required for the Xbox 360 controller to work on your computer and configure your controller settings on the emulator.