Cannot be performed because of an I/O error?! (please help)

[GoodaBrine XD]

I was just using my computer how I usually use it yesterday and that it gave me a blue screen. It then restarted itself and said "Operating system wasn't found". I freaked out. I tried doing this tutorial https://www.wintips.org/fix-operating-system-was-n0t-found-error-on-windows-10-8-solved/ But didn't work due to "Cannot be performed because of an I/O error". Please help, I cannot lose 950 gb+ of my data. ;-;

 

[rgd1101]

If there data that you cannot lose. where is the backup?

Might be hardware error. If the data is worth the money, go get professional data recovery like https://www.seagate.com/services-software/recover/in-lab-recovery/