Mac Pro Internal RAID problem

I'm using a Mac Pro octocore 3GHz Intel Xeon with 8GB RAM. We have three 750Gb Seagate drives that are swapped together in RAID-5 via the Mac Pro RAID card (not my personal choice). Anyway, the RAID set has disappeared and, when I perform RAID Utility it doesn't recognize the RAID card. When I do Disk Utility my drives read like this:

698.6 GB ST3750640AS P Media

That's the system drive in Bay 1. Not part of the RAID.

The next:

ST3750330AS Media

That one is in Bay 2. It doesn't appear to be online.

The next says this:

698.6 GB ST3_INVALID_PFM Media

That one is in Bay 3.

The last one says:

698.6 GB ST3750330AS Media

That one is in Bay 4.

Based on this information, I'm not sure if the RAID card failed or if one of the drives did.

Anyone have an idea? I'm clueless about Mac's internal RAIDs. Externals seem so much easier to me.

If you have three drives set up as RAID 5, then one drive failure should not take the RAID set down. From the Disk Utilities readout it appears that the drive on Bay 2 is missing totally. Even so, a RAID 5 should kick in the extra data to make up for the missng drive until it is replaced.

However the drive in Bay 3 mentions 698.6 GB ST3_INVALID_PFM Media, what ever that means.
If two drives fail, for any reason a RAID 5 will fall apart.

Thanks. I guess my next step is to crack this baby open and see if it even has the second drive in it.