There are no AHCI drivers for XP.
XP support ceased 3 years ago.
Your board is nine years old and no longer supported: Intel® Desktop Board DG35EC Product Specifications
What drivers and downloads there are for your board can be found here: Downloads for Intel® Desktop Board DG35EC
If you insist upon running XP, you may want to try running in "XP MODE" as a virtual machine on Windows 7, for example.
As a last resort, you may want to try and find a version of Matrix Storage Manager or Intel Rapid Storage for XP, which may provide AHCI support. For this option, I am just guessing.
This message was posted on behalf of Intel Corporation
I understand you are looking for AHCI drivers for the motherboard model DG35EC.
At this stage, I would like to confirm if you are currently running an Intel® board DG35EC with Intel® chipset G35 (ICH7) or the Intel® chipset 945GZ with ICH8R. Please run the following utility and attach the results.
Intel® System Support Utility
In order to attach files, make sure you select the "Advanced Editor" option in the top right of your reply window. You will then be presented with an attach file dialogue at the bottom of the reply.
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