With Windows there is ALWAYS a chance it's a driver/software issue. I'm another frustrated Mac user.
I do keep an old IBM ThinkPad around for just this kind of thing however. The first thing to try is deleting the Desktop Software and the OS you downloaded and starting again. Maybe use a slightly older Desktop Software version. I'm still using 4.2.2 just because it never caused me any problems and folks were compaining about v 4.3. We're way past my version but it still works, even with my Blackberry Bold.
There is always a chance that you have a bad USB cable, but that's a pretty remote chance. It's more likely that the USB port on the computer is wonky than the cable being bad. So first try a different version of the Desktop Software and download the OS again, all from scratch. 95% chance that will fix it. If not, then try a different computer.