Assuming you went through the tutorial and followed the guidance on how to configure putty, I would suggest you start by checking to see if the FTDI cable is connected to the 6-pin connector (between the ethernet connector and the client usb port) on the board correctly. One of the wires should be black and connected to the pin labeled GND (ground).
If so you can press the reset button and see if anything shows up.
I've replaced the cable which has resolved the problem, I wouldn't have guessed it was this.
Thank you very much