Thanks for the input so far everyone. It's a laptop with windows XP.

I've seen that laps free doesn't support USB. All I want to do atm is get the decoder to talk to the PC via the serial port using the serial-to-usb cable.

It must work because it's the same setup the previous owner was using.

I don't understand how to get the drivers for the cable/s I have and don't want to buy another if I can help it as there's 3 or 4 there already.

There's no brand on the serial-to-usb cable. It just looks generic