doomu/iStock/Getty Images PlusFollow ZDNET: Add us as a preferred source on Google. ZDNET's key takeaways Most PCs from the past 15 years can run Windows 11.PCs sold with Windows 10 can usually upgrade after a registry edit.On older or unusually configured PCs, a third-party utility might be required.Editor's note: This article has been regularly reviewed and updated by its author to reflect new guidance since its 2022 publication. Are you the designated PC expert for your family and friends? The next time you get a call asking for help with a Windows PC, check to see which version it's running. If the System > About page says Windows 10, then they really need your help. On Oct. 14, 2025, Microsoft officially ended support for Windows 10, cutting off security updates for retail customers. Anyone who has ignored Microsoft's increasingly strident warnings and is still running Windows 10 is already several months behind, having missed the important monthly security updates starting in November 2025. And by Microsoft's own accounting, there are hundreds of millions of PCs still running Windows 10. Also: Microsoft's Windows Insider Program is no longer a confusing messTrust me. You really don't want to be doing anything on a PC that's missing months of security updates. So, what are your options? You can enroll in the Extended Security Updates program, which pushes the expiration date out until October 2026. That's only a few months away. Or you can upgrade to Windows 11. Unfortunately, that's not an easy assignment. If you try to upgrade to Windows 11 on a PC that's more than five or six years old, you'll probably encounter an error message telling you, in no uncertain terms, that old PC doesn't qualify because its CPU isn't on the official list of compatible processors. You will also hit roadblocks if the PC doesn't have a Trusted Platform Module (TPM) version 2.0, or if the TPM is not enabled. That might be the official policy, but as with everything Windows-related, it pays to read the fine print. If that PC is less than 10 years old and has sufficient memory and storage, then it's probably worth keeping, and you can upgrade it. Also: How to get free Windows 10 security patches on your PC - from now to October 2026Those pesky restrictions prevent you from automatically upgrading to Windows 11 using Windows Update or the Windows 11 Installation Assistant. Yet, as hundreds of ZDNET readers have reported over the past few years, there are documented workarounds for most PCs that were originally built for Windows 10. On devices that are more than 10 years old, though, especially those built using AMD processors, you might be out of luck. The instructions in this article take all those factors into account. Also: Windows 10 PC can't be upgraded? You have 5 options - and must act nowThese instructions also assume that you have a PC with an x64 CPU (not ARM and not 32-bit), running a retail or OEM edition of Windows 10 (Home or Pro), and that you are signed in as an administrator on the PC you want to upgrade. You also need sufficient free space on your system drive. The official requirements specify that you need 64GB of free space, but an upgrade should work with a minimum of 25GB to 30GB free. If you don't have that space free, you'll need to uninstall apps or remove files to reach the minimum. Which option should you choose? Please don't skip over this section.This article describes two upgrade options. To take advantage of the workaround described in option 1 below, your computer must meet all the other requirements for Windows 11. It must be configured to start up using UEFI, not a legacy BIOS configuration.Secure Boot must be supported, although it does not need to be enabled. (But seriously, folks, you should enable Secure Boot.)A TPM must be enabled; version 1.2 is OK, but a system without any TPM or with the TPM disabled will fail. Any PC that was originally designed for Windows 10 should include a TPM 2.0.To check these details on a PC you're considering upgrading, run the System Information utility, Msinfo32.exe, and look at the System Summary page. Pay special attention to the BIOS Mode value. If it says "Legacy," you'll need to reconfigure your system to UEFI mode (and convert your system disk from MBR to GPT partitioning) before you can install Windows 11 as a normal upgrade. Also: Windows 11 upgrade not working? Try my 5 favorite troubleshooting tricksTo see whether your PC has a TPM enabled, run the Trusted Platform Module Management tool, Tpm.msc. If your computer includes a TPM and it's turned on, this app will display information about it. Under the TPM Manufacturer Information heading, check the specification version to confirm that it is 2.0. If there's no TPM, or if the TPM is disabled in firmware settings, you'll see a message that says "Compatible TPM cannot be found." If you're unable (or unwilling) to change from Legacy BIOS to UEFI, or if you have an older PC that doesn't have a TPM option at all, you'll need to use the second option, which takes advantage of an undocumented hack that allows you to bypass the compatibility checks and complete the upgrade. Skip to the Option 2 section of this post for details on how to use the free Rufus utility to perform this upgrade. Finally, note that Microsoft added a new set of restrictions beginning with the Windows 11 version 24H2 update. These changes require a CPU that supports specific instructions: SSE4.2 and PopCnt. Most PCs with Intel CPUs from 2009 or later will meet this standard. AMD CPUs from 2013 or later should also meet these requirements. But it is impossible to upgrade to a supported version of Windows 11 on a PC that was built in 2008 or earlier. For details, see "Microsoft blocked your Windows 11 upgrade? This trusty tool can (probably) fix that."Also: Microsoft said these 400 readers couldn't upgrade to Windows 11. They did it anywayIf you plan to perform a clean installation of Windows 11, you can boot from installation media and run Windows Setup. That option skips the CPU compatibility check completely (but still requires a TPM and Secure Boot support). After the installation completes, you'll need to reinstall all your apps, restore your data files, and tweak settings to personalize your system preferences. Want to avoid all that hassle? Choose the option that's appropriate for your hardware. Option 1: Use this simple registry edit With this registry edit, you can bypass CPU checks and accept any TPM version. Please be aware that this option requires that you run the Setup program from within your current Windows installation. You can't boot from a USB flash drive and upgrade to Windows 11 this way. This process requires four steps. You need to make one small change to the Windows registry. For more than three years, this change was documented at Microsoft's support website, but the company removed those instructions in December 2024. (Here's an archived version of that support article.) This change tells the Windows 11 Setup program to skip the check for compatible CPUs and to allow installation on a PC with an older TPM (version 1.2). The usual warnings apply when working with the registry; I recommend you make a complete backup before proceeding.Open Registry Editor (Regedit.exe) and navigate to the following key:HKEY_LOCAL_MACHINE\SYSTEM\Setup\MoSetupIf the MoSetup key doesn't exist, you need to create it. Right-click the node for HKEY_LOCAL_MACHINE\SYSTEM\Setup in the left-hand navigation pane, then choose New > Key. Name it MoSetup and press Enter.Also: Wiping your Windows laptop? Here's the simplest way to erase all personal dataSelect the MoSetup key and then right-click in any empty space in the pane on the right. Choose the option to create a new DWORD value. (Don't choose the QWORD option!)Replace the default name for that value by typing the text AllowUpgradesWithUnsupportedTPMOrCPU, and then press Enter. Then double-click the new value and change the "Value data" box to 1. The result should look like this: