How to Switch from BIOS-Compatibility Mode to UEFI Mode

When installing Windows® 7 or Windows Server® 2008 R2 on computers based on Unified Extensible Firmware Interface (UEFI), you may need to switch from BIOS-compatibility mode to UEFI mode.
Some UEFI platforms support booting into a BIOS-compatible mode, and it is not always apparent whether UEFI or BIOS is the default boot option. On these computers, you might be required to use the UEFI boot options to explicitly start in UEFI mode. Otherwise, Windows Setup might run in BIOS mode, which does not give you the advantages of UEFI.

How to boot a computer in UEFI mode

Different UEFI firmware implementations support different methods for handling the installation operation. The processes for booting the computer into UEFI mode for the Windows product DVD or to Windows PE are the same:

Instructions

1. Insert the installation DVD or USB flash drive, and boot the computer.
   
2. When the firmware starts to initialize, press the key that opens the UEFI firmware boot device menu, such as Esc.
   
3. Select an EFI drive, examples: EFI DVD/CD Drive, EFI USB Drive, or EFI Network Drive. You may be immediately prompted to press a key to boot from the drive to continue.
   The firmware uses the UEFI-specific boot information to boot into either Windows or Windows PE for UEFI.
   

   Note
   On some computers, you may need to manually select the boot files. For example, select Boot from file, and navigate to the file: \EFI\BOOT\BOOTX64.EFI on your boot device.

   
   

If the computer does not have a Boot from EFI Drive option:

1. Use Device Manager's Firmware option and select Boot from EFI Internal Shell.
   
2. Use the EFI internal shell, as follows:
   
   1. Start the EFI internal shell from the EFI boot menu and select the drive with the Windows product DVD or Windows PE. The following example assumes that the drive is Fs0:
      
      
      Shell> Fs0:
      

   2. Start the EFI boot application. For example, on an x64 system, run the following command:
      
      
      fs0:> \EFI\BOOT\BOOTX64.EFI
      

      For an Intel Itanium system, run the following command:
      
      
      Fs0:\EFI\BOOT\BOOTIA64.EFI
      

   3. After the application starts, you may be immediately prompted to press a key to boot from the drive to continue. Press a key to continue booting from the installation media.
      
   4. After the installation is complete, you can check whether Windows used the EFI boot environment by running DiskPart and verifying that the drive is formatted using the GPT file structure and that the ESP and MSR partitions are present.