Unable to reinstall Windows with rufus bootable USB

I have been successfully running Windows 11 v24H2 on an ASUS E403SA VivoBook. However, while executing some disk partitioning tasks, the system froze and was powered down. Now the system opens into the legacy BIOS screen when powered on and the boot menu only offers "Enter Setup" Here is what I've observed and done since the crash.

* Attempt to reboot failed
* Boot menu initially offered "Windows Boot Manager" as an option but system entered recovery mode
* Attempt to reinstall Windows with bootable media on USB drive failed
(Windows 11 can't be installed on disk 0 partition 2 (The selected disk is of the GPT partition style)
* Used diskpart from cmd to convert disk from GPT to MBR
* From a cmd prompt, entered >bootrec/rebuildbcd
( Identified 0 Windows installations; System32>c:\boot is corrupted and unreadable)
* Downloaded latest firmware (E403SA.301) and successfully upgraded the BIOS with the Easy Flash utility
* Boot menu now only offers "Enter Setup"; Windows recovery mode is no longer available
* Attempt to reinstall Windows with bootable media is not possible because the USB drive does not appear in Boot Override on the Save & Exit screen of the Legacy BIOS
* Main screen of Aptio Setup Utility verifies that American Megatrends 301 is the BIOS version.
* In Boot screen - Changed FastStart to [Disabled]; (Launch CSM is also Disabled at this point)
* In Security screen - Changed Secure Boot Control to [Disabled]
* Returned to Boot screen - Changed Launch CSM to [Enabled]
* Boot menu still only offers "Enter Setup"
* Legacy USB Support is [Enabled]
* USB Mass Storage Driver Support is [Enabled]
* Mass Storage Device 1.00 is [Auto]
Note: Installation Media is on a bootable USB drive created with rufus v4.8 using an MBR partition scheme, BIOS (or UEFI-CSM) target system, and NTFS file system.
ASUS Support site: "If there is nothing in the boot option, it means that the device cannot detect media storage correctly."
?Do I need to use FAT32 rather than NTFS? If so, rufus does not offer FAT32 for this .iso file (5.6GB) on this 32GB device..

I'm out of ideas. Thanks in advance for any help.

Regards,
John

futbolfan said:

However, while executing some disk partitioning tasks, the system froze and was powered down.

Click to expand...

What tasks exactly? Were you working in a live environment?

Do you have another PC? Just wondering if you actually saw two disks listed from diskpart (system drive + USB device). Or maybe it didn't see the system drive, and you accidentally overwrote the USB device with your commands.

Booting the same USB drive off another PC would test if you clobbered it.

glasskuter: Merging and resizing C partition
garlin: Good thought! Not the issue though because I was able to boot another MBR system from this USB drive.

One more idea: The Windows media that you made, did it contain only a single edition of Windows? Apparently Rufus had a bug related to that in 4.8 and so a 4.9 version that fixes the issue has been released. You might want to see if that works better.

futbolfan said:

Merging ... C partition

Click to expand...

With what?

hsehestedt: It was worth a try but using rufus 4.9 did not fix my issue.​

On the premise that a picture is worth a thousand words, the boot menu shown in the attached image is what I see with a tested bootable USB drive inserted. Simply put, my computer cannot detect media storage correctly. I need to figure out why. Events leading up to the crash and corruption are moot at this point.