We have a Dell T610 that has been acting as our mail server for about 4 years.  It is RAID 1 Mirrored Drives 0 and 1.  Awhile back, Drive 0 died, and we replaced it, I put the drive into the case and slid it into the server, and the RAID rebuilt no problem, and noth drives lights were green...fast foward 10 months later, and drive 0 fails again.  We order a new drive, slap it in again..the lights flash for a second, but it never detects it and syncs up with the other drive.  I troed a new drive cage, and another new drive...same story, light falshes for a couple second, but never comes on, does not detect drive, and cannot sync the raid and come out of degraded mode?  Any ideas what is wrong?  Thanks in advance.