It could be the video card. If you have another known working video card available you could plug it in and see if that solves your issue.  
Alienware aurora r6 wont post, and it won't turn on peripherals like keyboard and mouse, so I can't boot into bios or anything to try to flash. It is flashing 3 and 6 amber lights on the front so I thought I needed to make a bios usb recovery device, I have tried that, but because it won't turn on monitor, keyboard, or mouse I can't do anything. I have no idea what else to do, I have tried pulling the cmos battery and power cable for a minute like the bios recovery steps from the alenware bios recovery steps I found, but there is no change. Please help! I appreciate all your help in advance!
Aurora R6, wont start peripherals