Thanks gLk*zaP got it to work.
My experiences:
I have a P5E-VM HDMI mb(G35 ICH9R), E8400 Windows XP Pro (32-bit) where I wanted to enable AHCI in BIOS.
I am planning to add another hard drive to install Windows 7 RC1 and enable AHCI but didn't want to keep switching between AHCI and IDE when I wanted to boot between the hard drives for the various OS's.
I tried downloading from Intel the latest Storage Manager Software and expanding it as suggested. Just could not get it to work. What I did tried to do was hit
Start/Run and pointed it to the download, nothing, a dialog box popped up and said it could not find the file.
I found a workaround. I downloaded from Asus their latest
Intel Matrix Storage Manager Driver for my mb. Unzipped it and found the
IaStor.sys file and did as you suggested dropping it into
C:\Windows\system32\drivers\ Ran the
AHCI.reg file. Restarted the computer, went into BIOS and changed from IDE to AHCI and rebooted. It started fine and windows found new hardware I picked cancel and ran the program I earlier downloaded from ASUS. All is well. Now in device manager I see under
IDE ATA/ATAPI controllers Intel ICH9 SATA AHCI controller
Something weird though, I tried downloading
Ahci.reg file in Firefox and it wouldn't save, I tried with IE8 and its worked.
Onto phase II adding a new hard drive and Windows 7.