So both methods have similar steps and I will simply repost the steps for each method.
Use the Windows 11 Media Creation Tool to created a USB Drive Boot. Download here
Step 1: Back up your system, off the system. Back up to an external hard drive or USB drive.
Step 2: Enter the BIOS. On the Dell Latitude restart the system or from a cold start, press the F12 key before for the Dell logo or at the latest when you see the Dell logo. You will see a message that says you are entering ONE TIME BOOT MENU.
Step 3: Once in the BIOS look first for SETTINGS>GENERAL>BOOT SEQUENCE then Enable UEFI (After you do this you WILL NOT be able to boot back into Windows 10, but do not worry. Remember you created a USB key Windows 11 install from the Media Creation Tool before you got this far.
Step 5: We now need to enable TPM 1.2. The Dell Latitude does not have TPM 2.0, but Microsoft will allow users to install on systems with TPM 1.2. You simply have to agree to a warning message that also says you may not get updates, but you do get updates.
Step 6: In the image below enable Lagacy Option ROMs to boot from. This will allow the BIOS to load the option to boot from the USB key you created.
Step 9: Now click EXIT in the BIOS and if asked to SAVE say YES.
The Laptop restarts.
Again press the F12 key at the Dell Logo. It will again enter the ONE TIME BOOT OPTION.
But this time DO NOT enter the BIOS, you will see the option under Legacy Boot to boot to the USB Drive. It may have a different or odd name, but USB will be in the name. Choose that.
Follow the instructions and choose to do a fresh or clean install.
About 1 hour later you are running Windows 11.
Windows 11 Install on Dell Latitude Option 2
First download the Windows 10 Media Creation Tool and create a Windows 10 USB Install Drive. So choose to save the Windows 10 install files to the USB Drive.
Then follow the steps above, exactly including backing up your laptop. Follow Step 8 above but this time you are reinstalling Windows 10. So why can't you just boot back into Windows 10? When you change the option in BIOS from Legacy boot to UEFI the "file" pointing to the MBR on the Hard Drive has altered. So what was in Legacy BIOS to look for the Windows 10 boot files has been altered, so reinstalling Windows 10 created a new Boot record for UEFI.
Now once Windows 10 is installed there is a great deal of work from here.
Go to SETTINGS>WINDOWS UPDATE and download ALL Windows 10 updates until you see the update 21H2 installed.
Now we get to edit the registry. Here is the source for the following information >CLICK HERE<
Press Windows key + R and type in REGEDIT
Then look for and create the following
- Microsoft recommends against installing Windows 11 on a device that does not meet the Windows 11 minimum system requirements. If you choose to install Windows 11 on a device that does not meet these requirements, and you acknowledge and understand the risks, you can create the following registry key values and bypass the check for TPM 2.0 (at least TPM 1.2 is required) and the CPU family and model.
- Registry Key: HKEY_LOCAL_MACHINE\SYSTEM\Setup\MoSetup
- Name: AllowUpgradesWithUnsupportedTPMOrCPU
- Type: REG_DWORD
- Value: 1
- Note: Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.
The above registry key change tells the Windows 11 install process to ignore the TPM security check.
You will now need to download the Windows 11 ISO files, they are huge, over 5GB. Click >THIS LINK< to download them.
If you updated to Windows 10 21H2 then you can install from the ISO file from within Windows.
After it has downloaded Double click the ISO file then Double Click SETUP, follow the instructions, it may take more than an hour.