Disk Boot Error message appears if don't have windows 7 cd in DVD drive

I have the most bizarre problem, well it is bizarre to me at least and I can't find a way around it.
I have just built a new pc with 2 x 1TB Samsung Spinpoint F1 HDDs and Samsung and Sony DVD-RW drives and a copy of Windows 7 Ultimate 64-bit.
I have run the installation process for Windows 7, and it boots into Windows 7 perfectly when the installation DVD is in the Samsung DVD drive (I just let it skip over the 'press any key to boot from cd'), but as soon as I remove the DVD i get the dreaded 'Disk Boot Error Insert System Disk and Press Enter' message. I have tested this several times and it always does the same thing. The motherboard is currently an Asus P5N-D based around 4gb Kingston Memory and an Intel Core 2 Duo 3Ghz processor although this will be very shortly upgraded to an Intel i7 920 chip.
I have tried changing the boot order to boot from HDD and not CD first, formatted and reinstalled windows and tried the repair options from the Windows DVD but I still cannot change the message. Any ideas would be greatly appreciated.

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