I bought a Windows 7 laptop a few months ago and I installed Win500 and the moment I plugged in the cable the machine asked me if I wanted to load the drivers. It pointed to the website and downloaded the drivers and within 2 minutes of that I was saving the 5 V-folders I have on my Pro-106 to the machine with no problem.
I'm using the same cable as you have and my advise, uninstall any drivers, then plug in your cable and let the machine find the appropriate driver. Once it's installed it will tell you, it only takes less than a minute and you'll get a notification. Just check in Device Manager under Ports to be sure your cable is connected and has assigned a com port.
I use my cable for my Pro-164, '2055. '106 and '197 and it works every time without a hitch. Also be sure to plug the cable into the computer FIRST, then the radio.