change bad scsi controller on raid1

Hello,
I have a Windows 2000 server standard edition. The physical disk has 2
volumes. The "system" volume 0 and "data" volume 1 are configured with a
software RAID 1.
I have a failed redundancy on the "system" volume but not on the "data"
volume. Both physical drives are connected to an external Adaptec SCSI
39160/3960D Ultra 160 SCSI adapter. This is the second time this has
happened in less than a year. I believe I have a bad SCSI controller card.
How do I replace the controller in the existing OS with a new controller?
Can I install the new drivers on the existing OS prior to installing the
hardware and then reboot hoping for plug n play? I have a boot.ini file
configured and will break the mirror to find out if it's a bad drive, and
hope to resync another RAID1. I just want to avoid this issue anytime in the
near future again. Thanks for you input.

Joe