Hey I am helping a friend with their business server that went down.  Originally it would boot up and see no boot device.  We replaced the RAID card and now it says RAID status degraded.  Where do I go from here?  It should be a mirror RAID.  I believe one of the 2 drives may be failing, how do I determine which one, and then how do I replace it and rebuild the RAID to get it going again?

Thanks!