I have a focusrite 2i4, it should just be "plug and play". Windows should come with all the necessary drivers to support the device. Mine has always worked flawlessly, though I'm just using windows 7 at the moment for HW (I generally avoid windows like the plague it is).
You may want to check other things though, if two machines are both not working for you then it may not be the computers at all but something else. Are you sure the amplifier/speakers plugged into it are working correctly? Are you saying you hear music when using the headphones? (You have the main volume knob turned up, right? )