Hi, I installed SSD in the second CD drive bay and it's been running for about 2 years. On Sunday I turned the computer on and it only boots to the Windows partition which is on another HD. Booted from CD and Disk Utility does not see the drive. So I thought the drive was dead but I connected it to my mac air with a sata to USB adapter and it showed up fine. Then I stuck it back into my Mac Pro and it worked again. Since then I turned it off and on maybe twice and everything was fine. This morning the same thing happened only boots to Windows. So I bought another SSD cloned my original SSD and stuck that into Mac Pro and it doesn't work. Same problem. I took the CD drive out and connected one of the SSDs using the same connection as the CD drive was using. Same problem. Tried the other drive same problem. I put the CD drive back in and it works fine in Windows. So I am at loss what the problem is. If it's not the drive and not cables then what is it, the system board? Anyone has any clues as to what else to try? Thanks for any help.