Strange things can happen when trying to downgrade from Vista to XP.

In this case, an Asus F7SR laptop needed to be downgraded.

I boot from the XP CD, and it soon tells me:

setup did not find any disk drives installed in your computer

After some searching, I figure its due to BIOS running the hard drive in AHCI mode.

The standard XP CD is not capable of detecting AHCI drives (at least not without making slipstream CDs, or other fancy footwork).

I look in the bios, but there is no way to switch back from AHCI to ATA mode (so that xp installation can detect the hdd).

I do some searching on the net and find the generally suggested solutions are

– switch from AHCI to ATA mode (I cannot)

– slipstream the XP (I don’t really want to do this unless I find myself doing a lot of Vista downgrades)

– Put the XP sata drivers onto a floppy (laptop has no floppy, so a usb floppy drive is an option), and use the SCSI option when the XP CD starts up.

It just happens that I have a USB floppy drive (this is the first time I’ve used it in 3 years!)

But finding the XP AHCI drivers proves difficult.

The Asus website only has vista drivers (and only eSATA drivers).

While at the ASUS website, I see that the latest bios is “203”… the laptop has “202”.

The 203 bios only has a short description: “support both xp and vista”

I download the bios, use the usb floppy to update the bios… its surprising how many BIOSes will still not upgrade via a USB drive!

After the BIOS upgrade, there is now a bios option to operade the hard drive in ATA mode 🙂

After that, the XP installation was typically easy.

Installing XP drivers was more difficult… and thats a story for some another time!