So, which Bios are you on? I forgot which but either A03 or A04 fixes this whole 8 beeps thing... I decided to flash them in order from 2-5 just to be sure, because I went from 2 straight to 4 and had some issues with it's stability... but that's just my paranoia perhaps...
Anywho, what you need to do is install the Alienware software on the OS, which is both the On Screen Display drivers and the Alienware Command Center (and also install the drivers for the intel graphics as well, you'll want them...) then once you have them installed and reboot a time or two... then on the laptop you have a special key combo... FN+F7 which will during the OS idle change the system to switch from internal graphics to dedicated graphics...
For some odd reason in the Bios, it only shows either one or the other, whichever one is active, you never see both integrated and discrete.
Hope that helps...