S7-1200 cpu hardware malfunction

Hello
I have 1214C DC/DC/DC CPU which I can't communicate with it through pc. When I'm Trying to search the cpu in tia portal I can't find it.
The plc was working properly but suddenly it's status lamps goes as following
Run/stop flahes green and yellow
Error lamp is always red
Maint lamp flashes yellow
Also when I connect ethernet cable between pc and plc
Link lamp always green
RX/TX always off
Any help will be appreciated.

You can try an Extended Go Online.
But the most likely answer is that the PLC has failed, and that no amount of going online will fix it. If this is the first time that one in the machine has failed, it could just be bad luck. If others have failed then you need to look at protecting the PLC from voltage spikes.

I agree trying to go online is pointless. Are there IO modules connected to it, if yes then remove them and try restarting it.
Either way if you have or can get a hold of a memory card that would be your best bet a trying to reset it and hope that gets it going.