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PC boot stuck on blinking underscore screen after restarting


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#1 Manav20

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Posted 26 June 2018 - 03:15 PM

Hi everyone,
This is my first post on this forum. There are several threads on this website for the same problem but I couldn't find a solution that works for me.
So, I was using my PC normally. It started to lag a bit, even though disk and RAM usage were normal. So I restarted it. Since then, I am stuck on a blinking underscore screen. After the GIGABYTE logo, I see a black screen with a blinking underscore on the top left corner. I can access the BIOS settings, etc. Surfed through dozens of forums but couldn't find a working solution.

To try to fix this, I created a bootable USB for Windows 10 Pro x64 April update (the version that is/was currently installed on my system). When I went to the boot menu, it showed my internal hard disk and the bootable USB drive that I had just connected. For the USB drive, it showed two options, one was "HP xxxxxx" (there was the model name/number of the pendrive in place of the X's that I don't remember), and the other was "UEFI: HP xxxxxx". It was the same with just 'UEFI: ' added to its name. I selected the second one. It took me to the Windows setup and I sighed in relief. I selected the languages and there was the installation screen. There, I clicked the option to repair windows (present on bottom left corner of the setup window). It said it was unable to repair it. Went back and clicked the install button (present in the center). When I arrived at the screen to choose partition to install Windows on, it showed the list of all partitions with free space on each of them. But the setup couldn't install windows on any of them as it said "Can't install windows on a GPT drive". Did some research and found this link which explained the error: https://answers.microsoft.com/en-us/windows/forum/windows_10-windows_install-winpc/windows-10-installation-issue-cant-install-windows/ec4114d6-a036-457d-bec8-139dc77c5898
It says that it was because I had selected the UEFI option in the boot menu. The HDD needs to be UEFI compatible if the user wants to install Windows on it through the UEFI option. It suggested to either format the HDD through command prompt to make it support UEFI, or to use the other USB option from the boot menu (the one that didn't have UEFI in its name). I can't format it as it contains tons of my important work and pictures. So I went back to the boot menu and selected the first USB option. But that option too brought me to the blinking underscore screen. When I select that UEFI option, it takes me to the setup, but the first USB option doesn't, I don't know why! So I chose the UEFI option again, went fo Windows installation screen and started command prompt. Ran the following commands:
chkdsk
Sfc /scannow
Bootrec.exe /fixmbr
Bootrec.exe /fixboot
Bootrec.exe /rebuildbcd
They didn't report any errors and were unable to fix the issue either.
I also tried system restore from there but it said that I need to select an OS in order to use systy restore and asked me to restart the PC and selecting the OS. In short, this option was useless too.

Here's all what else I have tried:
1. Tried restarting the PC several times.
2. Tried reinserting the RAM, CMOS battery and hard drive SATA cables.
3. Tried the above method many times, using CMD, trying to get the first USB option (non UEFI one) to work.

Nothing worked for me! This is not something that needs to be mentioned but I'm facing extreme sorrow because of the situation as I don't want to lose my data. I hope anyone would be able to help me out here. Also, I'd like to thank you in advance for reading this message patiently.
Lastly, if it's just a software issue, there's a method that came across my mind while typing this post, but I am unsure whether it will work or not. Here's what I was thinking:
1. Using another PC to install a lightweight OS like Ubuntu on my pendrive.
2. Connecting that pendrive to my PC and try to boot into it.
3. When the Ubuntu OS boots up successfully, then I connect an external HDD to the PC and copy all my files from my internal HDD to the external one.
4. And then using the Windows bootable USB to access the windows setup and format the internal HDD to install a fresh copy of windows.
What do you guys think? Will it work? Can an OS installed on an external drive access the contents of the internal HDD?

Any other suggestions would be greatly appreciated. I'd like to thank again to you for your valuable time. :)

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#2 JohnC_21

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Posted 26 June 2018 - 03:38 PM

You can download the new Hirens Boot DVD based on Windows 10 and use it to copy your files to a USB external drive. Right click the iso and select Burn Disk Image.

 

https://www.hirensbootcd.org/

 

You can also use Rufus with the iso file to create a bootable USB flash drive.

 

https://rufus.akeo.ie/



#3 Manav20

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Posted 26 June 2018 - 08:22 PM

You can download the new Hirens Boot DVD based on Windows 10 and use it to copy your files to a USB external drive. Right click the iso and select Burn Disk Image.
 
https://www.hirensbootcd.org/
 
You can also use Rufus with the iso file to create a bootable USB flash drive.
 
https://rufus.akeo.ie/


Hi John,
Thankyou for the quick response. Appreciate it. I'll give it a shot in a few hours and see how things go.
Also, do you have any idea why this could be happening? I've been using PCs for 12 years and have never encountered this problem before. My current PC has completed its 4 years last week. So I thought it could be the hard fisk failing. But that doesn't seem to be the case as the windows setup did show all the partitions amd their sizes.

#4 JohnC_21

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Posted 26 June 2018 - 09:09 PM

Because Windows setup shows partitions does not rule out a bad drive. I don't have experience with this version of Hirens but it should have a HDD diagnostic program on the disk I would run the short and long tests if available. 

 

If this is a UEFI motherboard then I would highly recommend you install Windows 10 with UEFI enabled which would require the disk to be initialized as GPT. You can use the BC clean install guide BC member Brian posted.

 

https://www.bleepingcomputer.com/forums/t/667627/doing-a-completely-clean-install-of-windows-10/

 

But, I am not sure why you received the error stating you could not install on a GPT disk. A GPT disk is required when booting from UEFI firmware. 

 

Once you recover your data we can attempt to repair the computer using the Windows 10 install disk. If your personal data on the computer only resides on the one hard drive I would highly recommend you recover it first before attempting the repair.

 

Edit: I can't say why this problem happened, it could be anything from a bad update to a failing drive. I would also recover your data before doing the hard drive test because the test could send a failing drive over the edge making data recovery more difficult.


Edited by JohnC_21, 26 June 2018 - 09:13 PM.


#5 Manav20

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Posted 26 June 2018 - 10:15 PM

Sorry, I didn't exactly remember the error message. It was "Windows cannot be installed to this disk. The selected disk is not of the GPT partition style"

#6 JohnC_21

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Posted 27 June 2018 - 07:37 AM

Okay, I understand now. The OS was installed using Legacy mode on a MBR disk and not GPT. As you posted, that can be fixed on a reinstall. 



#7 Manav20

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Posted 28 June 2018 - 08:25 AM

I made the bootable USB again using the same pendrive. This time, I used Microsoft USB/DVD tool. After completion, when I connected it to my PC neither the Normal option nor the UEFI option took me to the Windows setup. Both of them showed the same blinking underscore screen.
So I took the pendrive one more time to another PC. This time, I used Rufus and changed the option of partition to MBR in Rufus' options and created the boota le USB.
When I connected it to my PC, it didn't show the UEFI option this time in the boot menu. There was only one USB option. I selected it and it took me to windows setup.
Now, I opened command prompt (Shift+F10), typed 'Notepad' and hit enter. In the notepad, I pressed Ctrl+S and it opened the file save dialog. It was a trick to use windows explorer. In the dialog, I opened every drive and checked my folders and files. They were safe and were intact.
Before this problem occurred, a day earlier, I had moved some files, around 70 GB, from E: drive to the C: drive which left only 15GB free space on it.
So now, I am using that save dialog box to free up some space on the system (C:) drive. It had only 15 GB of free space left. Moving those files back to the E: drive.
After that, I'll close the notepad and cmd and will try to continue the windows setup and will let you know how things go.

#8 JohnC_21

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Posted 28 June 2018 - 08:31 AM

If are going to do a clean install did you backup any data files in USER including your browser bookmarks?

 

At a command prompt type 

 

diskpart

list disk

 

Is there an asterisk under the GPT column on your Windows disk? If not then the hard drive is MBR. I don't understand why your USB doesn't boot when UEFI is selected using Rufus and a Windows 10 iso.



#9 Manav20

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Posted 28 June 2018 - 09:03 AM

I am currently copying the Desktop, Documents, Videos and Downloads folders from C:\Users to E: drive. Those were the only important folders in C drive.
So I don't mind doing a clean install. Rest of the important data resides in D and E drives.
I'll check what you asked for after the copying of files is completed.
Thanks

#10 Manav20

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Posted 28 June 2018 - 09:14 AM

It doesn't show an asterisk in the GPT column. Here's a screenshot:

#11 Manav20

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Posted 28 June 2018 - 09:16 AM

Screenshot

Attached Files



#12 JohnC_21

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Posted 28 June 2018 - 09:32 AM

That is showing a Dynamic disk for some reason. For a normal install this disk should be basic.

 

https://docs.microsoft.com/en-us/windows/desktop/FileIO/basic-and-dynamic-disks



#13 Manav20

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Posted 28 June 2018 - 02:23 PM

I just wanted to let you know that I've successfully completed the Windows installation. The previous windows installation went into the Windows.old folder, so I didn't lose any data. Have restarted the PC 3 times since then, and it's booting up normally.

All I did was to change the partition scheme to MBR from GPT in Rufus, and I was successfully able to install Windows.

rufus_en.png

I still can't understand how and why all of a sudden that issue occurred. Also, I didn't get why the CMD that I have posted the screenshot above of showed the free space on my HDD to be 465 MB, when it was more than 170 GB. I noticed it now when I looked at the screenshot.

Whatever be the reason, I am happy that my PC is fixed now!  :bananas:

Thanks for your precious time, John. Appreciate that. :)



#14 JohnC_21

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Posted 28 June 2018 - 02:49 PM

You are Welcome, and thanks for posting the update.






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