SBServer 2003 Will not mirror

Here is the issue. I have SBServer 2003. Changed hard drives to Dynamic. Keep in mind primary hard drive is partitioned hard drive and is IDE. Both hard drives are same size. Started mirror on partition one which is my system drive. All went well. Started to do 2 partition of hard drive mirror. The process had gotten all the way to 50% then SBServer said unknown hard drive. Then drops both hard drives off. Restarted computer had to go back into bios make boot it from hard drives again. Boot fine system partition will synch. with mirror but if I try to do the partition 2 again it gives me the same error. But after it does a synch with system partition disk management says that my mirror drive is unhealthy. Both hard drives are brand new. Does any one have a theory on this one? What am I doing wrong? Or is this 2003 problem? How do I correct this problem.