Firstly the esata port on your laptop would be controlled either by the chipset itself or in some cases by a secondary controller chip. Now if you dont see a stand alone chip then it will be listed under "onboard" devices.
as for the ACHI / IDE reset.
1.Exit all Windows-based programs.
2.Click Start, type regedit in the Start Search box, and then press ENTER.
3.If you receive the User Account Control dialog box, click Continue.
4.Locate and then click the following registry subkey: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
5.In the right pane, right-click Start in the Name column, and then click Modify.
6.In the Value data box, type 0, and then click OK.7.On the File menu, click Exit to close Registry Editor.
Note number 6, as in the instructions above, which came from Microsoft, that the Value in the registry entry showen in Number 4, must be set to 1. Then reboot, go in to the bios disable AHCI mode, then boot back in to Windows Vista, and Windows Vista will install the IDE driver, and redetect any harddrives in the system.
However if the person has used the Intel Matrix Storage driver for the AHCI driver, that the user most likely will not be able to uninstall the Intel Matrix Storage driver.