1771 communication error

Dear all. We use PLC5/40e for a appliction. We use Lithilium pin, without Memory card. With PLC/40e we use Ethernet port connect with RSview32 PC., Now, It have problem with PLC,PLC is shocked , program is empty.We can't ping Ip address of PLC. We use Bootp program, but did'nt recorgnize this PLC. Why do you know?.
Thanks.

That you know that the CPU is empty must mean that you have gone online via the serial port (channel 0), or the default DH+ port (channel 1A).

Set the IP address manually.
If not successful, try to clear the memory intentionally (remove battery, shutdown, wait 30 seconds, power up again, reinsert battery).