I have an Alienware M15x, 940MX processor, 16 GB RAM, 512GB M4 SSD, and I was running Win7 64bit. I backed up the disk and ran Win 8 setup. Setup appeared to go well through multiple reboots.
After the last reboot, it simply stopped after POST at "Press F2 for bios setup". I have tried powering off, reducing RAM to one stick, removing MOS battery. Now, it gets to the screen with "Press F2 for setup" and "Press F12 for boot options". If I press F2, I get a single beep only. If I press F12, nothing. I cannot get into the BIOS to change boot options to boot from another disk and restore.
I do have the latest BIOS. I am going to try replacing the CMOS battery, but I don't think that is likely to help. The computer has been fast and very reliable until now.