I've got some news
I've downloaded and installed repsnapper and the FTDI drivers on windows.
When i connect the reprap to the pc with the usb cable, Windows find a new hardware. But when i try to connect the printer with the green button "connect to printer", it remains light green only for few seconds and than it turns off. The port is com3 (and i think it's correct, anyway with the other ports the light remains light green even less), the speed 19200 (also this i think is correct).
All the electrical connections are ok, i've tested them.
Now, I think that the only possible problem is a software one
, i downloaded repsnapper from here: http://svn.kulitorum.com/RepSnapper/MSVC/Release/RepSnapper.exe
I really don't know how to solve...