Replacing a faulty Mitsubishi FX2n series PLC

Happy Xmass colleagues,pls do help me out,I am stranded!!!

The task: Replacing a faulty Mitsubishi FX2N-80MR/MT series
PLC on an injection blow mold machine.
The fault: when powered with 240VAC supply,its power led stays
on but its Error led fully blinks every second.
Challenges: Non of its programming softwares(MM+ ;FX-WIN ; GX
developer) could be provided.
My Action: I was given a similar new(spare) plc which came
with only its manual and USB-to-RS422 interface
cable and the cable driver CD. So I downloaded a
free GXdeveloper-8 software on my laptop.I install
the cable driver and connected my laptop and the
faulty PLC to see if I can diagnose the fault.
My Result: I was Unable to establish communication between
the PLC and my laptop. Also I did thesame
connection for the new PLC I was given, still
no communication between my laptop and new PLC.
Can the machine work if the new PLC is connected.

Dear Colleagues,I strongly feel my approach may be wrong, please help out.

As far as I know, blinking error LED on fx series signifies program/syntax/parameter error. The program maybe erased or corrupted.If your new PLC is supplied by machine maker, I would assume it is pre-programmed before it was delivered to you. IF not, then you will have to load the same program as the original PLC has, otherwise, your new PLC would definitely not work on your machine. If you were able to save the program then you could just upload, if not, you should input the ladder manually with reference to the machine ladder diagram. Otherwise, you can contact the machine maker or do yourself the reprogramming work, designing your own ladder.
As far as communication failure is concerned, check your communication parameter and cable.

If you downloaded the Demo software it will not allow communication with the plc you will need a purchased copy