New Graphics card now windows can't find my HDD.

[Mimalmo]

Ok so here is the problem. I got a new graphics card and power supply. I opened up my PC and plugged both in and I didn’t put in the drivers first. I have heard that could mess it up, but that’s not all. All I get when I boot windows is “Hard-disk drive failure”. I need help as this is my parents PC, but I am just upgrading it for a better gaming experience. If anybody has any ideas please tell me. I have already tried booting without the new graphics card, but I still don’t know what to do.

 

[Neospiral]

Can you access the hard drive by plugging it into another computer?

 

[Mimalmo]

Can you access the hard drive by plugging it into another computer?

I don't have any other computers to test that. Every other computer is a laptop so it wouldn't fit.