>>Evan, thanks for the greatly detailed response. Unfortunately, I'm in no position to try most of what you suggest, mainly because the only CD/DVD writer I have is on the bad system. Also the bad system has SATA drives an both of my others don't.
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>How about removing the drives from the RAID to eliminate that as a problem? There will be another connector on your motherboard that will connect just a single SATA drive. Then after adjusting the boot sequence order in the BIOS try booting with one, if that doesn't work try booting with the other.
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>If you want to save the repair shop costs, it might be worth it to transfer the burner to one of the other computers.
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>To access the the SATA drives from your other computers to copy off data, it might be worth the money to buy a SATA/USB connector for about $25. http://www.ncix.com/products/index.php?sku=17762

I just brought the thing to the shop... labour supposedly still under warranty.

The thing about the RAID C: - if that turns out to be the problem (my guess is now the graphics card) - is that RAID has apparently proven to be useless!

I'm not worried about all my working data because it is all on a separate drive on the system.

I'm anxiously awaiting the shop's determination.

cheers, and thanks again.