[cannot comunicat with vision120]

hi i was woriking on my controller,
and suddnly i lost connection with the controller, and i am not able to coconnect to it any more,

after few times of turning on and off,  bootster apeared on the screen and in the model filed on my pc  apeard the word boot

, i decided to download OS  (Communicaton pc settings>> dowaload OS)

still i cannot connect the plc 

how can restor the communtication please