Hi all ,  
I am a new member in this forum ,  
my NVR Hikvision ds 7716ni-st was working very well,  
yesterday , I can't access to the NVR neither from VGA monitor ,  
neither from ethernet and neither from Rs232 !!! and I have no message . 
The NVR is powered , what can be the problem ?  
I need your help .  
Thank you .