Disaster Recovery

I have to mirrored drives in my NT 4 server.The system partition and the data partitions are mirrored. The primary drive failed so the secondary drive is now primary. However the system will not boot to this drive. I have to boot with a boot diskto get the server up. I have gone into disk administrator and broke the mirror and checked that the partition was active which it was. The boot files are on the proper partion but nothing happens without the boot disk. What am I missing?