RAID Help on P5AD2E Premium

Any assistance would be greatly appreciated.
I have a P5AD2E Premium with Silicon Image 3114 RAID.
The RAID is configured as a 10 with 4 drives and does not contain an operating system (I use it for data storage.)
I have had no problems with this configuration until a few days ago. Upon leaving work, I shut down the system and noticed it hung. In a hurry, I just held the power button until it shut down.
The next day I noticed it took an unreasonably long time to POST. When the operating system came up, the RAID was not there.
I rebooted and opened the Silicon Image utility. All four drives were there, however, in the logical drive section, there was a message of, "Invalid RAID Drive." Most options are grayed out and the utility shows no conflicts. I also noticed when I selected, "Create RAID Set" I received an error of, "Not enough single drives."

Do these symptoms strike any bells with anyone? The data on these drives would literally take weeks to rebuild, so I'm not wanting to mess around with it much without some direction.

Any help would be greatly appreciated.

Bob