PC with Windows 10 won't boot after CPU/motherboard change

Question

I have a PC with Windows 10. Had to replace the motherboard and CPU. Now the PC won't boot from C drive. Error message:

"An operating system wasn't found. Try disconnecting any drives that don't contain an operating system".

The motherboard recognizes the C drive since it shows in BIOS setup as expected.

Downloaded and plugged in Windows 10 Installation Media into USB. Tried to "repair Windows". Result: "Could not repair Windows".

Tried to reinstall Windows from Windows 10 Installation Media without loosing data. Got this error:

"The upgrade option isn't available if you start your computer using Windows installation media.

If a copy of Windows is already installed on this computer and you want to upgrade, remove the installation media and restart your computer. After Windows has started normally, insert the installation media and run Windows Setup."

The problem is that Windows won't "start normally" or at all.

Contacted Microsoft and was promptly advised to "reinstall everything".

In short: I have a PC with a perfectly "healthy" C drive that won't boot. The obvious solution would be to reinstall Windows from scratch. This however will take me days because I have a lot of software development tools installed with plug-ins, special settings, etc. Is there a better way?

Answer 1

There are a lot of driver changes and without proper cleanup of old drivers and installation of new drivers, changing the motherboard without reinstalling windows is messy.

However, your question specifically asks about booting the system.

A likely cause of this failure is that you were booting your system in Legacy/MBR mode or UEFI mode prior to the change, and the new motherboard is using the alternate mode.

Go in to your BIOS/UEFI settings. Chances are the motherboard is, by default, trying to boot in UEFI mode. Look for an option to enable Legacy/MBR mode. These options will usually be found in the boot settings menu of your firmware settings. If it is booting in Legacy mode already, then change it to UEFI.

Answer 2

The OP's previous motherboard, an ASUS Z-97-A, recently failed and has since been replaced with a completely different model.

This would have been fine had performing a clean install of Windows and all applications been a viable option; however, it has since transpired that reinstalling and reconfiguring the OP's development applications will be challenging and he wishes use different hardware without going the clean-install route.

Replacing the previous board with an absolutely identical model would have avoided this new problem, which is related to HAL (hardware abstraction layer) changes introduced by replacing the old motherboard, leaving the existing Windows installation expecting the previous model.

It is difficult to restore to dissimilar hardware. The problem is that the hardware-dependent Microsoft Hardware Abstraction Layer drivers are embedded throughout the previous Windows system's installation.

There are three main options:

1. Use the new motherboard and simply reinstall Windows to solve the HAL mismatch issues (undesirable in this case as the applications are complex to configure.) This option will, however, guarantee a perfectly stable system with the new motherboard.

2. Match the failed motherboard with an exact replacement, allowing you to continue to use the existing Windows installation. Windows won't even notice anything changed and will be perfectly stable. (Difficult as this motherboard is discontinued and a replacement would take time to arrive.)

3. • Motherboards and other hardware components can be replaced by running Sysprep on the old system before it fails, in order to make a hardware-agnostic image that can be migrated to different hardware. Unfortunately, the old motherboard has already failed and no such image exists.

   • An alternative to Sysprep would be using a 3rd-party tool, such as EaseUS Todo Backup, to "restore a system to dissimilar hardware." But even specialized 3rd-party tools require an emergency backup to be created prior to the previous hardware failing.

If I was in this situation, I would consider returning the different model board (if possible), and buy an identical one, even if that meant used or open box. The main problem with that is you would have to wait weeks for it to arrive. On one hand, this could save you having to reinstall everything from scratch but waiting that long for a part to arrive might not be an option if this needs to be functional as soon as possible.

It depends if you would rather spend days reconfiguring your applications after a clean install and having the system up and running much faster, or waiting a couple of weeks for an identical board to arrive and having zero configuration of applications.

Most people would probably go for the reinstall because most people's software configurations aren't quite as complex as this. It all comes down to exactly how difficult configuring these applications will be and how much of a delay you are able to tolerate before the workstation is fully operational.

If you are able to get the old system to boot using the new motherboard, that would be excellent, especially in the short term, but it would be a kludge; I wouldn't entirely trust a critical workstation with a different motherboard model if it wasn't either Sysprepped first or received a clean install afterwards.

Trying to patch up an unstable computer with HAL issues is much more frustrating than slowly and methodically setting up a new installation from scratch, at least in my experience!

Answer 3

The boot mode (Legacy / UEFI) is not the only BIOS setting that can prevent Windows from starting.

I recently had an issue with a PC that wouldn't boot Windows anymore. The BIOS battery died, and it wouldn't keep the settings anymore. Windows Boot Manager would start, but Windows would crash and start the boot repair, which would fail constantly.

I exchanged the BIOS battery, and had a look at the SATA settings in the BIOS. By default it was switched to Legacy (IDE) mode. Changed the setting back to the newer AHCI mode, and Windows booted again without a glitch.

You should check that on your computer, depending on what it was before, then it might be either Legacy or AHCI.

Depending on your PC and BIOS model, this entry can usually be found under Advanced Settings or Integrated Peripherals, and then SATA settings / Disk controller settings / IDE settings.

Answer 4

I used the post by user https://superuser.com/users/750903/appleoddity to diagnose what my problem was however I had to use a different fix. I was unable to change the BIOS to use Legacy, MBR, rather than UEFI, GPT, so I instead used the mbr2gpt utility to change the boot type of the drive.

Background

An old PC, as in built around 2004, that I had given my mother to use for email and such finally stopped working in 2018. My first thought was the Antec 500 watt power supply had gone bad but after it checked out fine, I decided it was probably the motherboard. So I put the PC to one side and gave my mom an inexpensive mini-PC that she has happily used.

Recently, after finding out that my Dell with an i7-7700K would not pass the Windows 11 check because the processor was old, I decided to reuse my mom's old PC after replacing the motherboard and processor.

I bought an i5-11400 CPU with an ASRock z590 Pro motherboard and a couple of 8 GB sticks of GSkill DDR4 32000 RAM thinking to reuse the hard disk which had Windows 10 Pro until I replaced the hard disk with a PCI-E Gen 4 M.2 NVMe drive. I think the 500 watt power supply to be adequate as using the i5-11400 onboard graphics, power required should be no more than 265 watts (65 watts for the CPU and 200 watts max draw for the mother board).

I removed the old motherboard with its CPU and replaced it with the ASRock z590 with the i5 and the Intel stock cooler. After a couple of false starts due to incorrect connections from not reading the manual ASRock provided, I was able to start up the PC which landed in the UEFI BIOS screens and refused to boot to Windows.

This posted question led me to the conclusion that the hard disk had Windows 10 Pro with the legacy MBR type of boot information rather than the newer GPT type of boot information.

At one point during my reading of articles on the internet, I found that in the case of an upgrade from Windows 8 to Windows 10, the boot type would remain MBR and my recollection is that this PC had originally been Windows 8.

Procedures

After several hours of trying to find where in the ASRock BIOS I could tell it to use Legacy rather than UEFI, I gave up on that approach and began investigating whether I could convert from MBR to GPT.

A number of articles and forum posts agreed that doing so required a reinstallation of Windows until I came across a forum post mentioning the mbr2gpt.exe utility.

MBR2GPT.EXE converts a disk from the Master Boot Record (MBR) to the GUID Partition Table (GPT) partition style without modifying or deleting data on the disk. The tool is designed to be run from a Windows Preinstallation Environment (Windows PE) command prompt, but can also be run from the full Windows 10 operating system (OS) by using the /allowFullOS option.

However my great happiness became gloom when I realized that in order to run the tool, I needed

computer running Windows 10 version 1703 (also known as the Creator's Update) or later

and I needed to boot from this disk that I could not boot from.

Fortunately I had a second Windows 10 PC that was up to date and I had a SATA disk enclosure with an external power adapter that would allow me to use the hard disk as a USB drive.

After installing the hard disk into the SATA to USB enclosure and booting the second PC, I turned on the enclosure and the hard disk appeared as a USB drive.

Next I brought up Disk Manager to make sure that I was referencing the proper drive. In my case the drive I wanted to modify was Disk 1.

Then I started the Windows command shell, cmd, in Administrative mode to allow the mbr2gpt utility to modify settings.

Then I used the command line of mbr2gpt /allowFullOS /convert /disk:1 and watched the conversion which took about a minute.

I then shutdown the secondary PC, unplugged the USB enclosure, removed the hard disk from the enclosure and installed it into the case for my new PC then booted the new PC.

After several minutes as Windows reconfigured itself, rebooting and updating a couple of times, Windows came up and I was able to log in.

The next step I need to do is to connect the PC to my LAN and update it properly. The last step will be to purchase a Gen 4 1TB NVMe drive, clone the hard disk over to the new drive and I will then have an up to date PC ready for Windows 11.

Answer 5

I suggest a reinstall because you changed the motherboard. A lot of driver change would happen, even if it would had boot a clean install would remove anything there from the old mainboard.

Next time if you want to prevent a full reinstall you would had to run a sysprep inside Windows before installing the new mainboard. So its a last command you issue and you close the OS.

sysprep remove know device and when the PC restart it start the redetection like when it install.