If by reg hack you mean enabling the AHCI driver by changing a registry value, that's how I got it to boot in AHCI mode in the first place, otherwise it's a BSOD before the Windows screen. Enabling that doesn't disable IDE mode.
>Omen<;5606412My point in the above reply was to do the reg hack before you switch SATA modes to make sure the reg is set right for the mode you select. If you can't find it Googling, let me know, and I'll look for it again. ;)
I've tried that on my board, and while the drives were installed fine, and even when I rebooted they were fine, the next time I restarted, I got nothing but BSODs and had to revert. Worth a shot though, can't really do worse with a BSOD when you're having a problem with BSODs. =p