Changing a partition away from ‘system’

I installed 3 partitions (NTFS) to Sun hardware – C: and D: are mirrored RAID1 and one holds my OS (win2k3 R2 standard), the other, SQL. A third partition goes to a Sun storage array, E:. My issue is that the E: partition states it is a ‘system partition’ and C: a ‘boot’ partition. How can I change E: away from ‘system’ without having to rebuild/reinstall everything from scratch?
Unfortunately, this server is in production, so I need to be very careful. Any help or advice would be greatly appreciated.
Thanks! 🙂