This is a simple one. Turns out you need to update the BIOS on the HP N40L. If you want, you can disable the NIC and continue with the install, however, it kills all your settings and was (yes, I did this) annoying to reconfigure.
Jump on the HP site (http://h20566.www2.hp.com/portal/site/hpsc/public/psi/swdHome/?lang=en&cc=au&sp4ts.oid=5153252), select Server 2012 R2, download and run the BIOS exe (you'll need a spare usb thumb drive through out this process). Once the program has formatted and installed the files on the thumb drive, place it in your N40L, reboot and it should automatically execute. Unplug the thumb drive and update to Server 2012 R2!