Unable to Download to Cortex

The first cortex I received had to be rma’ed for a replacement because I was getting a “usb device not recognized” error. Now that I have the replacement, I’m still having trouble.

After I updated the cortex using the IFI vexnet firmware upgrade tool, I was able to download code over direct usb connection to the cortex once, and only once. After that I just got errors every time I tried to download over usb. Even while I was unable to download over usb, I could still plug in the the orange usb-to-serial cable into the controller and download over vexnet.
After a few times, this now gives me a synchronization error every time.

Anyone have any suggestions?

Update: I just did the most obvious thing possible, which was trying a computer that DIDN’T have vista installed. It seems to work…

Actually, it stopped working after the first download on the other computer as well.

Moar Update: Uninstalling and reinstalling the prolific usb-to-serial driver made the usb connection suddenly work.

This sounds like a VexNet pairing problem , follow pairing procedures

Is your computer 64bit ?

It already figured it out, I had to uninstall and reinstall the prolific usb-serial driver, and suddenly I could download directly over usb.

The synchronization error was caused by the orange serial cable being damaged.