The problem with Alienware is it is made by Dell. The motherboard is most likely made by ASUS, Gigabyte or some other contracted OEM supplier to Dell's proprietary specifications and exclusive use. That means you cannot go to the motherboard maker, buy the same board and build your own Alienware.
Because these are made exclusively for Dell, they likely have a proprietary BIOS. And while you may be able to buy a similar board from the board maker that allows you to disable or change the logo (as I can with my Gigabyte and Ian can with his ASUS) you may not be able to with your "branded" board. So I am just saying, don't get your hopes up.
Did you look in your BIOS Setup Menu to see if you are able to disable it or change it? Not all allow you to change but I think most allow you to disable the "Full Screen Logo Show" option. If your menu has a "Quick Boot" option, on some systems, that also disables the displaying of logos during boot.
If using a 3rd party tool, I would also suggest you backup your current BIOS/CMOS information (if yours allows it) before making changes - just in case.