Can't Boot RAIDED G5 PowerMac

[hob]

I have a Dual-2GHz G5, 150GB internal, 150GB external + 300GB external.

I turned it off earlier, when it froze up (very unusual I thought), and when I switched it back on again, it got to the Apple logo and then froze without bringing up the spinny thing.

I inserted the DVD and booted from it, ran Disk Utility - I got a bit confused because there are several things attached to my computer, so I swtiched off and restarted with JUST the boot drive, which is the internal hard disk raided to the 150gb external via FW800.

It doesn't appear in the list. The other FW800 will, but for simplicities sake, I have unplugged it. The internal shows, the RAID set shows, but not the second disk. What can I do?!

 

[hob]

5 seconds later....

I was typing this thread on my powerbook, on my lap, infront of my powermac. There was a stranging beeping sound coming from somewhere. The DVD span down, the beeping stopped, and the 2nd FW800 disk appeared in disk util...