Echo in HyperTerminal is a setting: File>> Properties>> Settings>> ASCII Setup>> "Echo characters typed locally".
Local echo should be *disabled* and you should *still* see echo.
The echo comes from the fact that these radios use a single pin for transmit and receive, and thus the TX and RX lines are tied together inside the radio. Since you see no echo and no data when you try to initiate the clone, something is wrong with hardware. Since you have two cables, it sure sounds like the radio. Since you said you tried two radios, it sounds like the serial port. Since you tried two serial ports... well, not sure what to say :)
However, we can rule out CHIRP here since you aren't getting the beginning of the clone message from the radio.