Question Unable to boot, boot device LED constant red and blinking underscore.

LordHenryVonHenry

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The boot device LED has been consistently red while the computer has been consistently working fine for a few weeks now, after computer restarted, on boot goes through boot screens and then ends up with a blinking underscore prior to any windows screens.
The operating system is on an SSD which I have been able to access fine for file usage and according to crystaldiskinfo still has plenty of life left in it though it is worth noting the SSD is a good 8 or so years old.
I am in the process of creating a windows installation media to see if windows auto repair does anything.
Had to pop to the shops to get a new flash drive lol.

Am I right in presuming the fault is most likely the motherboard or some corrupted windows files on the SSD?

Thanks.
 
Am I right in presuming the fault is most likely the motherboard or some corrupted windows files on the SSD?
Multiple of possible reasons.
If you changed boot settings in BIOS recently;​
If you reset BIOS settings;​
If you updated BIOS;​
If boot device file system is corrupted;​
If bootloader is corrupted;​
USB device connected, that is interfering with boot process.​

Those would be most common reasons.
 

LordHenryVonHenry

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Multiple of possible reasons.
If you changed boot settings in BIOS recently;​
If you reset BIOS settings;​
If you updated BIOS;​
If boot device file system is corrupted;​
If bootloader is corrupted.​

Those would be most common reasons.
I have made no changes to any of the hardware or software, not even a windows update, in the time since this problem materialized.

Upon running start up repair, in less than two seconds I got "Start up repair could not repair your pc" with no log file, leaving me not sure where to go next...
I guess I could try installing windows on the other SSD I have installed?
but that would only solve anything if the problem is files on the current SSD.
 

LordHenryVonHenry

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Diskpartshows the drive is still alive atleast (I think).

Disk0 is a harddrive I use for storage.
Disk1 is the SSD which windows is installed on.
Disk2 is an additional SSD I use for games and storage.
Disk8 I presume is my external backup drive though I'm not sure where it got 5589 from...
Disk9 is the flashdrive installation media.

I'm not sure why it lists the free space so low but I presume that's space not taken up by volumes?
I don't know, slightly beyond my computing knowledge lol

 

LordHenryVonHenry

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Another possible reason - BIOS battery has died and in result BIOS settings have been reset.

Disconnect removable drives and check boot settings in BIOS.
Make sure correct drive is first in boot order.
After disconnecting everything except mouse and keyboard, boot order is still listed as
Samsung SSD 840 Pro series
HL DT SD BD RE
Generic-USB3.0
So SSD first, after exiting boot menu still end up with just blinking underscore, red boot LED on the entire time.
 
It's possible bootloader is on some other drive. This can happen, if multiple drives were connected during installation of windows.
Try putting remaining drives as first in boot order.

To determine, which drive contains bootloader, post screenshot from command output:
diskpart
list disk
select disk 0
list partition
select disk 1
list partition
select disk 2
list partition
list volume
 

LordHenryVonHenry

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Imgur: The magic of the Internet

Three images there showing partitions on each disk and the volume list.

PC was a prebuilt but custom from chillblast long time ago now.

The large 2TB SSD I added myself later so only the small SSD and the hard drive (listed at 0,1 in those images)
were present when windows was installed.

Worst case I can try installing windows on the large relatively new SSD, though that is far from convenient as I don't have an external drive enclosure or a spare desktop computer and hence no convenient way to copy everything off of it first.
 

LordHenryVonHenry

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Where do I disable UEFI boot, don't see an option for it in boot settings?

Those settings being advanced boot settings in ASUS UEFI Bios Utility which are the only ones I know how to get to, also checked under main and advanced.
Under Security Boot Parameters can switch between "Windows 8 UEFI" and "Other Legacy & UEFI" which is already selected.
 
Last edited:
You can try repairing bootloader. That would help, if bootloader somehow got corrupted.

diskpart
list disk
select disk 1
(select 238GB SSD)​
list partition
select partition 1
(select 350MB partition)​
active
format fs=ntfs quick
exit
bcdboot G:\windows /s D:

Assuming here 237GB windows partition is G: , 350MB bootloader partition is D : .
Make sure drive letters are correct. They may change in recovery environment.
 

LordHenryVonHenry

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After disconnecting both other drives I get:
"An operating system was not found, try disconnecting any drives that don't contain an operating system."
Boot device LED is also no longer on.

(Yes I double checked which drive I left plugged in)
 

LordHenryVonHenry

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Slight update:
Got an external drive enclosure so current intention is to copy everything off of my spare SSD, then clone the contents of the faulty SSD to it, then try and boot off of that.

Failing that, I guess I'll have to just install windows and start fresh on the spare SSD, and lose like, 8 years worth of program installs lol.

All of that is presuming the problem is the SSD, and I have no idea what else it could be.

Any suggestions for the best way to go about any of this would be greatly appreciated.
 
Do you get those weird symbols in BIOS too?
This could signal about damaged/overheated graphics card.

If not, then that could possibly be boot sector corruption.
Might be - your SSD has reached end of write cycles and getting corruption because of this.
 

LordHenryVonHenry

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Do you get those weird symbols in BIOS too?
This could signal about damaged/overheated graphics card.

If not, then that could possibly be boot sector corruption.
Might be - your SSD has reached end of write cycles and getting corruption because of this.
I only got those symbols once after having left it on the "no operating system found" screen for half an hour or so.

No issues on the bios settings nor have I been able to replicate those symbols again.

Is it worth attempting to clone the contents of the SSD to another and trying to boot from that?
I have some old programs I couldn't get again easily if I reinstalled windows.
 

LordHenryVonHenry

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Attempted to clone the SSD, was unable to boot from it.
Installed windows fresh on spare SSD and booted into windows fine (though graphics card seems to be having issues as it's fans spin up briefly then power off again)
I guess I'm stuck with starting fresh?
 

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