Fix: PC not Booting After New CPU Install

Switch from UEFI to CSM or Legacy mode to troubleshoot the issue

5 min. read

Updated onOctober 4, 2023

updated onOctober 4, 2023

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Key notes

Upgrading your computer CPU to a new and better version helps improve system performance and increase speed and multitasking capabilities. However, users complained about PCs not booting after installing the new CPU. This guide will outline the fixes for the problem.

Alternatively, you can read our detailed article aboutlow FPS after CPU upgradeand what to do if you experience it on your PC.

Can a CPU cause a computer not to turn on?

Yes, it is possible for a new CPU installation to cause a computer not to turn on. There are several reasons why this could happen, and some are listed below:

Fortunately, the problem is fixable, and we’ll take you through some basic steps to get around it later in this post.

Moreover, you can check out our article aboutWindows 11 not bootingand how to force start it.

How long should a new CPU take to boot?

Moreover, during the boot process, the computer performs several tasks, such as initializing hardware components, running the power-on self-test (POST), and loading the OS. Hence, all these determine the time taken to boot.

What do I do if the PC won’t boot after a new CPU install?

Before trying any fixes, observe the following preliminary checks:

If the PC still doesn’t boot after trying the preliminary checks, proceed with the solutions below:

1. Clear CMOS

Following these steps, you have effectively cleared CMOS (complementary metal-oxide-semiconductor) settings on your motherboard. It is essential to do this as it activates any recent hardware changes to the motherboard.

2. Switch from UEFI to CSM (Compatibility Support Module)

Note that these steps vary depending on your computer’s manufacturer and BIOS/UEFI version. Hence, you can consult your motherboard’s manual or the manufacturer’s website for detailed instructions for your system.

In addition, you may be interested in our post aboutinstalling Windows 11 on an unsupported CPUand the easiest way to go about it.

Likewise, you can check our article about ways to fixslow boot issueson your Windows 11 PC and make it faster.

Should you have further questions or suggestions regarding this guide, kindly drop them in the comments section.

Fix: PC not Booting After New CPU Install#

Can a CPU cause a computer not to turn on?#

How long should a new CPU take to boot?#

What do I do if the PC won’t boot after a new CPU install?#

1. Clear CMOS#

2. Switch from UEFI to CSM (Compatibility Support Module)#