I wasted entire day backing up my files and then trying to install Windows 7 RC x64. Everything was fine until first restart when my AHCI bios couldnt find available devices/ports. But first: my PC was running in AHCI mode for months with Vista64 and win7x64beta installed; no problems. Until today. Here what i did: 1.boot from windows 7 rc dvd, 2. deleted all partitions, created new ones, formated and started the installation process; 3. After couple of minutes the installer restarts my computer (as always) but the booting stops on AHCI bios. Now I tried to restart again but no go: stop on AHCI bios screen, only solution I could think of was to enter bios and turn off AHCI (and start new windows installation), but to do it (enter bios) I need to get pass AHCI bios screen. So I cleared CMOS which reseted my bios settings and allowed me to enter bios and set my SATA ports to IDE mode. From now on it was trouble free and I am writing this from Windows 7 RC. But what was the problem? Is it Windows 7 RC? If not then only other explanation would be bios version I am using: it's F6c which is in beta state and it updated Intel AHCI bios version to newer one; but it run well without problems until that Win7 installation. Anyone running Win7RC on HDD in AHCI (or RAID maybe?) mode succesfully? Here are my system specs: Motherboard: Gigabyte EX38-DS4 GIGABYTE - Product - Motherboard - Overview - GA-EX38-DS4 CPU: Intel Core 2 Duo e6750 2.66GHz GPU: Gainward GeForce 8800GT 512MB RAM: Patriot DDRII 2GB (800MHz) HDD: Western Digital SATAII 250 GB WD Caviar Blue 250 GB SATA Hard Drives ( WD2500AAKS ) PSU: Tagan 500W System: Windows 7 RC 64bit PS. Forgive me my poor english; hope you understand what I wrote above.