I had a hell of a time today to install Windows-XP in my new PC (P5K-Premium, Q6600, 2x1GB OCZ memory, EVGA 8800GTS-320MB, WD7500AAKS , 2xSATA DVD-RW, P182). I set the BIOS to AHCI and during Windows install, I used the F6 method to load in the AHCI driver (obtained from the MB CD). Dring Windows install, I got this error: Driver_IRQL_Not_Less_or_Equal.... then - iastor - Address F722775A base at 7223000 Datestamp 46018619 I tried a few time and got the same error. Then I gave up and set the BIOS to IDE and during Windows install, I got another error, something System Error. I have 2 new hard disks. I tried WD7500AAKS first and repeated the whole routine to WD5000AAKS. Now I don't know what to do anymore.