I had a problem reading a radio last week. Although you could hear the connection tones, I would get an instant connection error when trying to read. Swapped cables, usb, serial, borrowed cables, etc. Tried all kinds of tricks. Got the blue screen of death several times. I grabbed another radio out of the batch I was trying to read, and found the same problem. Things were not looking good.
Turned out the radio for whatever reason did not like a system key (from an unrelated system) that was loaded. I killed the key and opened the software and it worked like a charm. Just FYI if that is of interest to anyone. I have never had that happen before.