enabling ahci in 32 bit

I recently upgraded XP to 8 using the cheapest method - downloading direct from Microsoft. This meant staying with 32 bit. After sucessfully setting up I realised that I had forgotten all about enabling AHCI so I Googled for instructions. Getting into the registry was straightforward enough but the part to be changed was not as expected. It would appear that the 32 bit registry is different to to the 64 bit one. Does anyone know the 32 bit sequence?

if your BIOS was set to AHCI when you upgrade , they are no need to change anything in the registry, the upgrade installer must have install the good drivers.

Slight problem here, I loaded 8 straight onto XP and the bios was set to ide. I dont think xp would boot in achi, although I didnt even try.

Google found instructions for me similar to Windows 7 but I never got them to work with the Preview versions or W8.

Fortunately I enabled AHCI on my mobo before I installed the 'Upgrade Version'