Alienware m14x one beep

Hi, I have an Alienware m14x and when I turn it on it beeps. It is just one beep which is supposed to mean there is a motherboard problem. I've tried a new motherboard which didn't work and it also says it could mean the BIOS. So I also tried downloading the new BIOS putting it on a usb and then holding end and the laptop comes on and doesn't beep but the fan comes on and it never goes any further. Does anyone have any suggestions? Thanks