Thank you for all the replies, it is helpful. i am asking since, i lost cd for hp 8100 computer and i am using another xp cd to install. it has pdf documentation files regarding ahci installation and at one stage it is said to run msdinst.exe to inject ahci driver. but no mention of where to find this program. i can manage Windows 7 AIK & windows 7 OPK, if that will do.