I recently wiped my main HDD to perform a clean install of windows however after choosing to do the advanced install windows alerts me that drivers for the HDD's are missing. When I go to load my drivers from my USB the setup gives me an error that it cannot find the driver files from the USB in the folder I stored them in however it detects the 32 bit versions I have saved. I proceed with those, choose the 64 bit OS and proceed with the installation however this just throws my comp into a boot loop when it reaches the restart part of the install most likely from the computer having the 32 bit drivers. The next time I try to install i proceed by loading the 32 bit drivers and then when told to choose the HDD to install the OS I click the load drivers button, this time it detects the 64 bit drivers however will not let me install them as they are not digitally signed. I have a feeling setting my HDDs to AHCI in my boot options will allow me to install without all of the driver problems. However I have been told that doing so would wipe my data HDD that I currently have all my stuff on.
But if all you want is to switch to AHCI sata mode just change the registry driver setting and then reboot and switch it in the bios (just look under let me fix it myself for step by step): http://support.microsoft.com/kb/922976#method1