Blank Screen on Bootup

I got an Alienware M17x R1 that's having problems starting up. It powers on, the lights come on except for the Menu/Alien Head and the Alienware logo on the monitor. You can hear the fans, hard drive, disc drive, but nothing appears on the monitor. I swapped every possible part over from another M17x R1 and it kept doing the same thing. I swapped: Hard drive, Video Cards, CPU, Monitor, Power Board, disc drive, and the mini board that's on top of the disc drive. Nothing seems to help. One time I did get a very very faint display on the monitor, but that's it.  Every part I swapped works fine in my other laptop which makes this very odd that it wouldn't work from swapping them over. I also tried 2 different motherboards. The service tag is: <ADMIN NOTE:Service tag removed per privacy policy>