I have a similar problem with my Asus X71Vn laptop that has two hard drive bays. Until recently everything worked fine with two hard drives or with USB drives. Now, however, if I have two drives installed (be it internal SATA or USB), the AMI Bios boots twice and one of the drives disappears. The machine boots normally with one drive in any of the SATA bays but if I install two drives there is a double booting and one of the drives disappears (this happens both under Windows 7 and Linux). My BIOS version is 207.