[updated] Aspire D150 dead on boot this morning

I own a three-week old Aspire D150 which was completely dead on boot this morning. My model is the 160GB/Win XP which I had reformatted to an Ubuntu 9.04/XP Professional dual boot. If it helps any, I had my partition table ordered as follows:

SDA1 - XP Professional
SDA2 - /boot
SDA3 - Swap
SDA4 - /

I had actually finished this setup last night, although I left off reinstalling grub until this morning (it was 3am). When I turned the machine on I received a message stating "No Boot Disk found..." Suspecting a hard drive problem I first tried to boot from two spare USB keys I had with Ubuntu 9.04 and Windows XP Professional installed.

The XP Professional key reported that it was missing files and could not continue setup (it had worked flawlessly not 9 hours before).
The Ubuntu 9.04 key would boot, but it reported DMA errors, and after the GDM initialized no hardware would work. I had to remove the battery to reset my laptop.

Suspecting a RAM problem I reseated it. No difference.

To eliminate the hard drive, I used a spare one I had laying around with a corrupted Windows Vista Home installation. It did manage to boot to the point at which the corruption stopped it.

So:

I cannot boot to any OS on the original hard disk.
I cannot boot from any external USB key device.

UPDATE: I was able to boot into a Linux environment and reinstall Grub by hand, through the use of a totally new USB key. I've since been able to boot back into Ubuntu 9.04 without incident. Strange and unusual. My Windows XP installation gives a generic "no bootable disk found" error still, and I'm ready to write off that whole partition.