Howdy super Brodyody,
Try downloading the BIOS update from support.dell.com directly. And then running it outside of Alienware Update. Once you have the new version installed, Alienware Update will stop prompting you to install it. Make sure to read the instructions carefully during the update, and have now other programs running. Most importantly, if you do NOT get a succesful update prompt, do NOT reboot. If it fails, you should try it again. If the second atempt fails, do NOT reboot, at that point call Alienware tech support. They should be able to help you recover before your system becomes unbootable. Good luck!