Hi, I have a 4,1 here that won't boot, powered on but then nothing on the screen. RAM light is not on, no beep or indicators. I tried resetting SMC, PRAM but there are no chime or sound coming from the internal speaker, visually checked the motherboard and cables connection, all seems to be good. Any suggestions, please. Thank you. Specs: Single hex 3.3ghz, 12gb Ram, Dual 1TB HDD, flashed GTX 680.