Hello

I am facing strange problem when i connect RB750 to my PC Network light on my LAN card are on But the other end of Cable connected to Router Have No light I cant access Router from winbox or Browser there is no ip or MAC address. I Try to Reset
Router Pressing Back Button Light Blink but after that no activity.I Know the reset process and done it successfully before but
now not working

It sounds like you have a hardware problem, but just to be sure have you tried replacing the cable, using a different Ethernet port, or changing your port settings to 10M Half duplex? If so, that router may just be bad.

Thanks I Guess its a router problem taking it back to Replacement

No problem.