The same named post is already in Sticky (#2), but closed for further posts. But I have a related question. The importance of this topic (enabling AHCI under already installed XP) is somewhat minimal nowadays, after the arrival of new techniques (NLite/DriverPacks etc) to integrate new AHCI drivers directly into XP install-CD. But my requirement is to change over my already installed system (WindowsXP-SP3 in DG33FB mother board with BIOS= Non-AHCI option) to AHCI mode. Now I know that in Sticky Topic #2 (Post #251) by MDGx says: "starting with Intel Driver version 9.6.0.1014, everything is simple, & extra cumbersome steps detailed in initial posts by puntoMX are no more needed!!" Sticky Topic #2 Post #251 by MDGx Now I cannot understand the very first Step itself here (infact Steps 1 to 3 above), since if you do that you will get a BSOD. i.e when you simply change the BIOS option to AHCI, & reboot a Windows-XP system, (as indicated in steps 1-3 above) it will result in BSOD. This is not NEWS, & this exactly is the problem the above (sticky) thread started to solve initially by PuntoMX, & then finally this Final Post & closing of the sticky thread . Can somebody show me some light here ...