Cant get my Computrainer(cycling hardware) to connect and talk to my computer.

I am connecting a stereo pin to a 9 pin adapter into your windows eight compatible serial to usb converter. I just upgraded this cable since the old ones drivers were no longer being upgraded. However the hardware I am attempting to interface with my computer is no longer working. The only change was from OS XP to windows 8 and this cable. Any ideas how I can get em to talk again?