Need to boot Windows 7 off of a GPT disk, thus needing to use UEFI, but I have a secondary OS that has AHCI drivers only, not IDE therefore I cannot run the system with IDE + UEFI, I need UEFI + AHCI. When I have it as IDE + UEFI the bios sees the hard drive and optical drives just fine, but when I turn on UEFI with AHCI the bios then declares that no bootable drives are found. After flashing back to the earliest I am able to boot off of a USB stick for the Windows 7 install which is allowing me to boot into the Windows installer, but if won't let me install on the drive claiming that the computers hardware may not support booting to this disk. Ensure that the disk's controller is enabled in the computer's bios menu, and the option to boot off of a CD/DVD is still not available as an option with the bios setup this way, and with the newest bios it would hard lock with a zero in the lower right corner of the screen and nothing else. Will not let me boot off off any device that is attached via sata when AHCI and UEFI are enabled period after testing, and will not even let me boot off of a sata drive when attached to a SATA to USB enclosure that I can boot from when either of those options are disabled (AHCI or UEFI), the moment you turn them both on, the drives are listed under the SATA options in the bios, but are not listed as bootable items under the boot menu, nor when you POST will it allow any of those devices as selections.