HP DC7700 will not boot after interrupted Windows update - need to recover RAID data

I have an HP dc7700 CMT with two hard drives in a mirrored RAID array. I forced a shutdown while Windows was applying an update -- I did it during that period when it says (do not power down or unplug your computer, because it clearly wasn't applying it. Anyway, my bad, and I did it secure in the knowledge that my system partition has been imaged (using ShadowProtect) last night and that I could restore that image by booting with the ShadowProtect CD. The system won't boot -- even to the initial BIOS screen, so won't boot from the ShadowProtect CD, and I'm up a creek.

So I have two concerns. By far the most important one is recovering the data changed since my last data backup yesterday. My data is on a separate partition from the system, although on the same SATA drives, which are mirrored. I suspect I cannot simply plug one of them in to an external SATA enclosure since they are members of a RAID array. Assuming the PC itself can't get rebooted, how can I get data off those RAID member disks?

The less important, though still important, question is how to revive this machine. I think it MIGHT actually be getting to the BIOS screen but is failing to show anything on the monitors. The reason I think that is because I reset the CMOS and tried rebooting according to HP's instructions (disconnecting the HD, CD, floppy) and turning it on to do a POST. After 5 or 10 minutes, even though the monitors are asleep, the computer beeped once, so it must be doing something. I have Matrox cards in there with three monitors attached. Can't get the computer to put anything on them, nor on the VGA.

Not sure what other information I can provide. Anyone have any ideas, especially regarding the data recovery?