WM_MOUSEMOVE will return a standard message to you. Loword lparam is x and hiword I believe is y.
WM_LBUTTONDOWN, etc can be used as well.
If the mouse is USB, and most are these days, you can also grab the input out of the RawInput API's. But they are a little trickier. You'll need to know the MOUHID codes..
Em...installing the mouse...., no enough Data to understand
what do you need