I turn the PC off and on and it works. yay, I think.
The next morning, the PC is off. I think "hrm, that's weird", turn it back on and it works.
Now the next morning, which was today, it wouldn't recognize my HDD. I put my ear next to the HDD (damn it's too quiet), and I can hear the discs spinning, so it's getting power. I have tried 2 different SATA cables in two different SATA ports.
I haven't tried a different HDD because, tbh, I cba. Was hoping there was some simple stuff I could test before I have to do that.
So yah, halp?