How to Install Windows 7 on a UEFI enabled Computer

We recently bought a Lenovo T-440s amd immediately loved it, except it came with a Windows 8 Professional, 64-bit. It had "downgrade rights" for Windows 7 Pro 64-bit. Unfortuantely, our corporate IT environment does not (yet) encourage Windows 8 especially in laptops nor desktops, so I really was obligated to downgrade it to Windows 7 Pro/Enterprise.

The T-440s is Windows 8 optimized and is UEFI and secure-boot enabled. As an IT professional, I am also interested in how UEFI works (later I'll write a blog after I successfully installed Kali Linux on dual-boot in a UEFI system) and if it indeed delivers to is promise. UEFI is explained in detail here. Microsoft also explains UEFI and how it is here.

Do note that UEFI systems behave differently depending on the model and brand of the computer. This how-to post is specifc to the T-440s. While the concept and the general procedures may be the same as with other laptops (i.e. Acer, Asus, HP, Dell, etc.) the behavior may differ slightly.

The Objective:  Install Windows 7 Professional 64-bit on a UEFI enabled Lenovo T-440s.

Before we begin, let us first discuss what are the differences between installing Windows OS in UEFI and in non-UEFI mode (aka Legacy Boot Mode)

1. UEFI installation of Windows 7 only works in 64-bit installations. 
2. UEFI does not work in Win XP. 
3. By default T-440s ships with Windows 8 and with UEFI and Secure Boot enabled. However Windows 7 normally is not for UEFI systems.  If your Lenovo Thinkpad T-440s ships with Windows 7, the settings may have been changed. 
4. The Lenovo Thinkpad T-440 does not have a CD/DVD Drive, you have to either attach a removable drive, or create a EFI-bootable Windows 7 USB Stick. 

Here's how:

1. Go to the BIOS Setup by rebooting your Lenovo Thinkpad T-440s then, repeatedly press F1 until you get to the BIOS Set-up Screen. 
2. Go to the <Security> Tab then disable Secure Boot



Step 2: Disable Secure Boot




Go to <Startup> Tab then set UEFI/Legacy to UEFI Only. Change the CSM Support Setting to Yes.
                     



Step 3. Set Startup to UEFI Only but say yes to CSM Support

Note: If you did not set CSM Support to yes, Windows 7 installer will hang at the windows 7   screen.



Save and Exit. Reboot the Thinkpad T-440s and this time, repeatedly press F12 to get you to the Boot sequence screen. Choose CD?DVD Media or USB if you are using a bootable USB stick installer.  
Proceed to the installation until you get to the partition part. Do not partition. Instead, press Shift-Fn-F10.
A command prompt will appear, type diskpart.
Type list disk to show the list of available disks. Take note of the disk you will partition. 
Give the following commands inside diskpart: 

            select disk (disk numnber)
       clean
       convert gpt
       exit


Continue with the Windows 7 Installation. Ignore the "cannot continue installation" error message. 

After you have finished installing, you can verify if indeed you are booting your Windows 7 in UEFI mode. On your first boot without the windows 7 installation media, go to C:\windows\Panther\setuppact.log. You would want to see if CallBack_BootEnvironmentDetect. It should say: Detected Boot Environment: EFI.  

And that's how easy it is done. Thanks for reading.