windows server 2012 r2 essentials

I had a power problem with my WServer 2012 R2 which I think I have solved. All the involuntary restarts played havoc on my RAID 5 Array and I lost a disk. It is a 5 disk system with each disk being 3TB. I have never had to rebuild a disk before. So I got a new disk, popped it in, made it a...