This was my configuration: Two 250GB internal HDs in RAID 1 configuration, 2 partitions as logical drives C: (OS and software), and D: (for data), each about 50% full. My game plan was to install another 120GB HDD internally, split up the RAID configuration and move the OS and programs from the old C: partition to the new 120GB drive -- my new C: drive. This way, I would now have 500GB on two internal HDs, exclusively for storage. And I have ordered a 500GB external drive to use for backup. (I already have an 80GB external drive -- that will be my backup for the OS and programs on C:.) I started the process last night -- got about halfway through the whole process. But I encountered some major difficulties. I am very much open to some solid advice so I can avoid these issues again tonight! Here is what happened.... First, I created an image of my C: partition, storing it on my external 80GB drive. I powered down and installed the 120GB drive internally, then powered up again. Running Acronis TI 9.0, I restored the disk image to my new drive. At this point I still had a RAID configuration on the other two drives. I shut down and went into setup to make sure that the #1 boot hard drive was set to the new drive, and I disabled the BOOT designation that had been assigned to the RAID drives. So far, so good. I booted up -- no problem. I powered down again and disabled the RAID configuration. I also removed one of my RAID drives (2 drives, exact copies of each other). I booted again, but my new OS drive was designated as the D: drive -- not C:. My old bootable partition was still designated as the C: drive. I tried to format this old partition, but had lots of issues with that -- the drive was still "being used by other programs" - I could not determine what was using the drive. I systematically deleted stuff from the drive, in the hopes of solving this problem, but I could not get the system to stop "using" the drive. So I was unable to format it from within Windows -- not in Safe Mode, either. I got around this problem ultimately by booting from the XP installation disk, and going partway through the XP installation procedures. Part of this process analyzes all the drives -- and offers the installer an opportunity to make changes to some of the disk configurations. It is possible here to delete unwanted partitions. So I deleted my old C: partition. When I shut down and rebooted, the old partition was gone -- it was now unallocated space. And the new boot drive was now designated as C:. Mission accomplished! But now.... I have to install the second RAID drive -- which ALSO has a C: partition on it! And a duplicate D: partition with the data. I plan to use the XP installation disk again to remove BOTH of these partitions, then to reformat the whole drive as a single drive. I have already created an image of my D: partition (data), which I will restore to this newly formated drive. I will remove the first RAID drive -- with the old C: partition that was replaced by unallocated space, and reboot to make sure all of my data that was copied to the new drive is intact. Then, I will re-install the first RAID drive, wipe out the remaining D: partition using the XP installation disk, reboot, then format the drive in Windows. Through all of this, I need to make sure I retain a second copy (image) of my D: partition (data) -- in case of a catastrophic error. Is there a simpler way to do this?