STEP 3: Recommended BIOS Settings: I don't have "Optimized Defaults" nor do I have AHCI mode | tonymacx86.com
DeployHappiness | Dell BIOS Update Utility (GUI Version Guide)
Desktop with Monitor, Dell Optiplex 390, Intel Core I5-2400 CPU @3.10GHz, 4GB RAM, No HDD, DVD-RW, Win 7 Pro Sticker (Verification), with 22" Lenovo L2240Pw0, Monitor, No Cables/Keyboards/Mouse, Appears to Function. [95152+6]