You enter UEFI F/W setup by pressing F1 key during POST
Navigate to "Startup" page and change the "UEFI/Legacy Boot" setting from "Both" to UEFI Only"
Exit UEFI F/W setup using F10 key to save your changes
You then boot the system from the Windows 7/Windows 8 installation DVD and perform a normal installation
After Windows 7/Windows 8 setup completes, you are no longer able to enter the UEFI F/W setup option when using the F1 key during POST.
NOTE: This only impacts certain OEM systems that shipped with Windows 7/Windows 8 preinstalled in BIOS Legacy Boot mode.
During Windows 7/Windows 8 setup, certain BCDEdit commands will be executed to configure the new installation. These commands may delete information in the BCD store that is necessary for the UEFI boot manager to load the UEFI firmware menu. Also, Vista, Windows Server 2008, Windows 7, Windows 8 or Windows Server 2008 R2 and Windows Server 2012 may modify the BCD store in a way that prevents the UEFI firmware menu from loading.
Contact your hardware vendor to see if there is a firmware update available to resolve this issue.
LOAD_OPTION_CATEGORY_APP bit of Attributes in Boot#### is deleted by bcdedit.exe /export, then bcdedit.exe /import /clean process. It may also be cleared by installing Windows Vista or later. This can cause the UEFI Boot Manager failure to enter UEFI firmware menu.