Bad news, the graphics card is probably dead

I haven't looked into the problem too deeply, but it's looking bleak.

The machine tries to boot with it installed, but it doesn't display anything. Not over HDMI, not over VGA. Nothing at all. The machine won't even display anything through the integrated VGA plug.

Maybe I was too rough with the card when disassembling, the heatsink removal was unnecessarily violent, after all.

Maybe I screwed the heatsink on a little too tight. After some thinking, the original thermal paste might not have been thermal paste at all, but instead a thermal pad that had been squashed to nothingness. I attempted to put the screws back to their original pressure, which might not have been a good idea with just thermal paste.

Maybe there's something I can do to make it work, maybe it still has some life, but I won't keep my hopes up. Just really hoping I don't have to buy another graphics card. Just in general.