cgsecurity.org

First of all, sys and hardware specs:
Win 10 home x64 Bits!

Core i 7 4790K,
ssd120gb for windows,
st3000dm001 3Tb Hdd - this is the magical one that has '3,86Tb'
Msi gaming 7 z97 motherboard...
all the rest is irrelevant at this point...

So i was playing Factorio, than i need to restart the game cause i put some mod on it, next thing i know, steam crash...so i reopen it, would not open at all...so i though i restart my PC..and so i did it, next thing i know my HDD is missing, on Win disk manager it show's up a misleading size: 3,86Tb..

When i try to inicialize thought windows disk mananger, it ask me if is MBR or GPT, i remember formatting to GPT cause i need one partition with such huge size, and i need more than 4 partitions on that disk (linux wise...)
so i set GPT, and select ok... says

the request could not be completed because of an i/o device error.

im trying testdisk, but no success so far..

Try a DCO (Device Configuration Overlay) restoration, it can be done using the disk manufacturer tools or via hdparm under Linux, something like If you need to create a Linux LiveUSB, read https://www.cgsecurity.org

If you still have the problem after that, you may have to contact a data recovery company.