Windows 7 64-bit install on Optiplex 790/990 with UEFI Mode

Summary: Install instructions for Windows 7 64-bit on a Ddell Optiplex 790 or 990 with UEFI Mode.

(from : https://www.dell.com/support/kbdoc to : https://lhgus813.blogspot.com )

 

Users may want to install Windows 7 64-bit on an Optiplex 790 or 990 with the Basic Input/Output System (BIOS) Unified Extensible Firmware Interface (UEFI) setting enabled. Here are some important items to note and a guide to install Windows 7 64-bit:

1. Please ensure that BIOS version 5 or newer is installed on the Optiplex 790 or 990 prior to the install.
2. Microsoft does not offer support for 32-bit Operating Systems (OS) in UEFI mode. Only 64-bit versions of Windows Vista Service Pack 1 (SP1) and later are supported client OSes.
3. Windows requires the OS partition to reside on a GUID Partition Table (GPT) partitioned disk. Master Boot Record (MBR) partitioned disks can be used as data disks. As defined in the UEFI 2.0 specification, a UEFI platform requires a dedicated system partition. Windows requires this dedicated system partition, which is referred to as the EFI System Partition (ESP).
4. You must have EFI supported media (DVD, USB memory key) present in order for the option to be displayed in the boot menu. If there is no EFI supported media in the drive during Power On Self-Test (POST), the UEFI option will not be displayed on the F12 boot menu.

Below is the install process for Windows 7 64-bit from a Dell Original Equipment Manufacturer (OEM) media for an Optiplex 790 or 990 with UEFI mode.

Note: There are other advanced methods to install in UEFI mode, like dropping to a command prompt during the install process and using Diskpart commands to create the GPT partitions. Users may also be using an imaging process to install in UEFI mode. These methods are outside the scope of this document.

 

WARNING: It is best practice to backup all data on the system. The install process involves formatting the hard drive and will erase all data.

1. Use the "F2" option at boot to enter the BIOS.
2. Navigate to the "General - Boot Sequence" section of the BIOS.
3. Verify that the "Boot List Option" is configured for "UEFI".
4. Apply changes and "Exit" the BIOS.
5. Insure that the Windows 64-bit media is in the machine.
6. Tap on "F12" at boot up to enter the one time boot menu.
7. Select the "UEFI BOOT" device and hit the "Enter" key.
8. The system will act like it is booting to Windows.
9. Choose "My language is English".
10. On the next screen, choose "English" as "Language to install:".
11. Choose "English (United States)" as "Time and currency format:".
12. Choose "US" as "Keyboard or input method:" and click "Next" to continue.
13. Click on the right arrow for "Install now".
14. Click on the checkbox for "I accept the license terms" and click "Next" to continue.
15. Choose the "Custom (advanced)" option for installing.
16. For the choice of "Where do you want to install Windows?" you may see the error message "Windows cannot be installed to this disk. The selected disk has an MBR partition table. On EFI systems, Windows can only be installed to GPT disks."
17. You may need to delete any existing partitions to move forward with the install process.
18. You can accomplish this by clicking on the link for "Drive options (advanced)" and deleting partitions as necessary.
19. This will create a disk with only "Unallocated Space".
20. Select that disk and click "Next" to continue.
21. The install process will begin and Windows setup will automatically create the necessary GUID partition table (GPT) and install Windows 7.
22. Allow the system to reboot and complete the install process as necessary.

 

the source of the article: https://www.dell.com/support/kbdoc/en-id/000150459/windows-7-64-bit-install-on-optiplex-790-990-with-uefi-mode