How Do I Get AHCI Features Back For Windows 7?

Yesterday I installed Windows XP Pro 64 bit and I may have screwed a couple things up for a good dual boot system. I plan on installing Windows 7 Pro 64 bit next but I thought I would get some good input before I proceed. To install XP I put the SATA controller in IDE, now I'm wondering how I can get the ACHI features back for Windows 7. I have a ASUS P9X79 Pro motherboard, I've been told that it has dual SATA controllers but I have no clue how to get it to run two different SATA modes. If this is something that can be done, can someone point me in the right direction to get started? Or suggest some options?

When I installed XP I did it on my reformatted drive that I had Windows 7 on. I left the C drive portion to be system reserve with plans of deleting it and installed the XP on the rest of the drive under "D" drive. I went to delete the C, System Reserve and the system won't let me. Is this something I can cure with EasyBCD? Or am I going to have to start over with an install?

One more question; Why would my XP install take up 860GB on a 2TB drive

Thanks for Reading: MudSpike...


Knows where his towel is.
Staff member
Thank you for the reply Terry
The second link comes up with a "Not Found" link for me but from what the first and third link say, I'm thinking that this is a "Do over!" From what I'm gathering; my old windows 7 install is still on the hard drive?


Knows where his towel is.
Staff member
No idea whether your old W7 is there or not. Just cautioning against trying to place an OS during install using Disk Letters.
The OS may not end up where you intended.
The boot files will always go to whichever partition is marked "active" in Disk Management even if that's not where you placed the rest of the OS, which could explain why it won't let you delete a partition you didn't think you were using, or it could be that that's actually where XP went.
Follow the advice in the last link post and make sure that the target space is also marked "active" and you should get your XP all in one place, and where you intended.
Sorry that link has expired.
A web search on the topic should throw up lots more advice of ACHI