hi am am new to the fourm i have a problem the RX led is always on and i cant download any sketches this is on xp any help is welcomed 
Maybe the COM port which arduino used is used by another program.
i have looked at this but i dont think it is and i dont know if it is important but the Rx led is always on even when not power via pc e.g 9v battery :P :-?
I think your FTDI chip might be blown.