Refer to microsoft article # 922976 .
Man why would you want to use a NON-Supported OS on a nice board like that come on in to this century Get W 7 64 Bit so you will not be limited to 3.3 GB ram ?????
Oh I am in the current century, but sadly not all companies who made software back in the xp era are around or their software never was updated to work in Win7. Yes I know xp mode if you own the professional edition (which I do) but if you are a gamer or have apps that need the directx api's you can't run them in xp mode (not unless Microsoft has totally revamped xp virtual mode in the last few days). So I run a hard drive with xp and a hard drive with win 7. I use a hot swap front mounted bay so the only hassle is waiting for the system to reboot.
In regards to ms article 922976, it refers only to Win 7 and Vista. It says to go to xp solution center for the applicable version for xp but there is none. So you can't use the MS autofix option. Those two reg entries only appear if you have got ahci drivers loaded. The problem there is no way to confirm you actually have it working. Since Intel refuses to at least provide a non-liable solution, warning that you could trash your install, suffer a performance hit and hence they won't be responsible if you take their possible fix and damage your install, your data, etc. However Intel if they are still supporting xp in their chipset drivers they could at least provide some help.
As I said I have tried the online suggestions but have no way to know if it is actually working correctly. Sure my system loads into windows xp. However I don't know if the device manager and the list it shows for IDE ATA/ATAPI is correct. I can confirm however that the Plextor 850SA does work in ahci mode, contray to some warnings about optical drivers not working in ahci or surviving a test conversion over to ahci and being recognized.
So I still hope there is a solid method to doing this and knowing that it is working on the z68 chipset.
But Robert thank you for that reminder about the age of xp and that link/support article#. Also after you factor in the video card, that ram number is more like 1.9-2.1gb (depending on what apps you load on startup - firewall, antivirus, etc.).
I save 64bit for Win 7 since developers have caught up in almost all cases to the difference between 32/64 in Windows 7. Sadly a few still have not made the effort, refuse to so you will have to upgrade to new hardware (looking at Logitech with this comment) or so they don't have their engineers and developers working on software/drivers which much like Microsoft supporting XP is not bringing in any new revenue. I can't totally blame them but at the same time, it is just good customer relations to make an effort. That is how they earn the goodwill and therefore loyal repeat customers for their hardware/software.
I have never tried this , But just a Idea what if you installed the AHCI driver with the F6 Method , or is it that you don't want to go through a complete fresh install. You might try the chat line and ask Intel would this work. ??