Well, disabling Int13H extensions in a PCI card firmware will remove that card from the list of bootable drives, so you wouldn't be able to boot from it at all then. Assuming that's what you want (for example if you're booting off the motherboard SATA ports and the SiI3124 card is getting in the way), then you could, in theory, just remove the BIOS for the card entirely or flash a dummy ROM over it, then (this has worked with cards for me in the past like this at least) let the driver scan/add the drives on the card during the Windows boot sequence. Hope that helps, -tij-