Suggestion Rqd for :Siemens PLC S5 115H CPU not coming to RUN status

We are having the following problems in SIEMENS S5-115H (redundant system):
1) both PLCs went into stop mode, when modbus connectivity used for other system

2)after removing the same connectivity,then tried to reset the PLC by toggling RN/ST as per the procedure, we are unable to get the Run status or flickering of LEDs as it should be.

3)when all communication cables with PLCs removed & only one PLC is kept for observation ,with the other PLC not connected to the first as well as in powered off condition.

4) the first PLC is behaving the same as aforesaid.

Our queries are as follows:
1)is there any other option available to make the PLC in RUN.

2)In PG, if trying to get the backup, we are getting file in this format ??????ST.S5D & not getting the configuration file ??????XR.INI.

3)Is there any option available for getting the ??????XR.INI.

4)how the memory is shared incase of S5-115H 942CPU. what the EPROM is having & what the RAM is having (program file/ config file)

5)PLC without EPROM is tried & found working ok with RUN status. But with EPROM, it is not coming to RUN status.

Please suggest any observation in this regards.

Thanks
Mitesh