Windows 8.1 startup stuck at blinking underscore, USB boot to repair computer doesn't work

[nattack]

Hello,

I left my desktop on sleep mode in the morning and when I came back in the evening, it was frozen so I shut it down. However, it wouldn't boot past a blinking underscore upon restarting, which I researched could be due to HDD failure or something to do with corrupt Windows registry files. I checked the BIOS, and my HDD was recognized, but wouldn't boot. I don't have a disk drive in my desktop, so I used a USB (loaded with a Windows 7 iso, then later Windows 8.1) to try and reach the "repair my computer" option from the boot up. At first, the USB boot drive wasn't recognized, so I switched from the Legacy option to UEFI, which enabled access from the USB. However, my computer now gets stuck when I try to click "repair my computer" or "Install now". I am unable to reach a command prompt or any other option that I think may fix the problem.

There were no hardware changes made prior to this condition, so I'm thinking perhaps it was a virus of some sort?

Anyways, here's some of the hardware in my desktop:

• ASUS Z-97a MOBO
  
  nVidia GeForce GTX 970
  
  Intel i-5 4690k
  
  WD Blue 1TB HDD
  
  Corsair Vengeance 16GB (2x8GB) RAM
  

I appreciate any assistance in advance!

 

[basroil]

Just sounds like an HDD failure, perhaps a motherboard one. Just take out the HDD and use an enclosure (or internal connection) on a different computer and see if it can be read from. If you can't read from it, it's broken. If you can read from it, the motherboard might be broken, and you can test it by loading up a linux livedisk (you can make one from USB just like the repair "disk"). If the livedisk works, it's a more complicated problem, if it doesn't, try clearing the cmos (there will be a jumper on the motherboard) and trying again. If it doesn't work after the bios refresh, then it's a bad mobo firmware or board itself.