Windows 8.1 automatic repair loop

Today, my pc with Windows 8.1 installed suddenly started crashing on start up, and then rebooting and showing the 'Automatic repair' screen. I tried solving this in multiple ways already:

I tried creating a USB drive with a copy of Windows 8.1 on it on my laptop, and then on my pc select refresh pc - when I insert the USB drive it says the inserted media isn't valid.

• I tried using startup repair, it just runs for a minute and then it says the problem can't be fixed using startup repair
• I tried a system restore, but it gives the error '0x80070057'. Unfortunately, there's only one system restore available

• I tried using the following commands in the command prompt:

  bootrec /fixMBR     
  bootrec /Fixboot     
  bootrec /rebuildBCD
  
  

  However, after the last line it says that no installations were found (I made sure to activate the windows partition using DISKPART)

I didn't recently install any suspicious programs, and I've been ruing Windows 8.1 for over a year now without any problems. Can anyone please help me? I really need to be able to use my pc