Recently I decided to reinstall Windows XP Pro on my home desktop. Yes, I know, Windows 7 is out and far superior but I have some music software that only runs well on XP as well as having already paid for XP… just bear with me!
I won't go overboard, but here are the relevant technical details: ASUS P5B Deluxe motherboard with Intel ICH8R onboard SATA controller and 3 x 250GB SATA HDDs. I used to have two of these in RAID 0 (yes, I have backups) but I decided that the performance benefits vs. just sensibly placing things on different drives wasn't worth the extra risk. So, for my reinstall I would be moving from RAID mode in the BIOS to AHCI mode.
I backed up everything, flashed the BIOS with the latest version (good time to do it when I am reinstalling anyway), set all my settings and flipped the ICH8R to AHCI mode. As I expected, my old XP install no longer booted as it was configured for RAID mode with the appropriate driver. Linux coped fine, though 
. I popped in the XP Pro SP2 CD, hit a key when prompted and watched the message: Setup is inspecting your computer's hardware configuration. After that, nothing. No chance to hit F6 or anything. Just a black screen. I even left it for ages in case it would finally realise it couldn't read the disks yet. No joy. Hmmm.
Basically, there seemed to be some issue with the fact that the setup CD could understand that there was an operating system installed but not properly read it and it was getting stuck. OK, no bother, whack in a Linux live CD and nuke the disks. In case you are interested, I like using badblocks in write mode but anything that destroys the partitions would do I expect.
Right, attempt number 2 (well actually a much higher number, but if you are reading this you don't need to follow my mistakes!): this time I get to the F6 prompt, add the AHCI driver from a floppy (drive hanging out of the side of the PC – why would I have a floppy drive on a modern PC?) and Windows sees the disks. Great! Actually, no. This time it sees 1 x 250GB disk and a 500GB disk that it cannot access (the old RAID array). Having selected AHCI in the BIOS and the AHCI driver this did surprise me. No problem, back in the BIOS and enable RAID then into the RAID BIOS and delete the array. Back in the BIOS again, enable AHCI.
Attempt number 3 and we have success! 3 x 250GB disks detected (after using the F6 option to add the driver) and I install Windows XP.
So in summary, if you want to reinstall Windows XP and go from one SATA controller mode to another, my tips would be:
- Break any RAID arrays in the RAID BIOS
- Delete any existing partitions on your disks
- Make the BIOS changes you require
- Boot to the setup CD and slipstream the correct driver
Simple when you know how! As an aside, I was installing from a SATA DVD drive and that caused no issues (I saw some people report that this is a problem). I know this wasn't part of the problem because I even had another 'donor' machine next to my desktop at one point so I could try installing from an IDE optical drive…
