[xubuntu] CD "Boot from first hard disk" works, can't boot to HD without CD.

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http://ubuntuforums.org – Just did a clean install of Xubuntu 12.04 amd64 on a new Western Digital wd30ezrx 3TB hard disk - no errors during install. The mainboard is an Intel dq35mp (dq35mpe) (which ran Ubuntu 10.04.4 with Xfce fine). When trying to boot to the hard disk, it stops at "no bootable device -- insert boot disk" (after I disabled "Boot to network" in the BIOS). When booting with the Xubuntu install CD (alternate ISO) from which I just installed*, I enter on "English" from the language menu, and then select "Boot from first hard disk", from which Xubuntu boots f (Hardware)